I noticed on ebay there is no way to tell “before” clicking Buy, that a Seller has selected not to ship to certain addresses or address types especially Postoffice Boxes, or P.O. Box addresses)
Here in Canada, the Canadian Postal Service is changing its policies for all municipalities that ise P.O. Boxes over this year, meaning that the P.O Box number MUST be on the shipped item address or it will be rejected at the Postal Outlet. You have to either send every seller you plan to purchase from to ask them if they ship to P.O Box addresses, or actually click to buy it, and if they don’t ship to P.O Boxes, you get an error and can not pay for the item through Paypal, and have to go through the frustration of trying to contact the seller and request them to send a Transaction Cancel Request, and then somtimes i get replies in Chinese Language from the Hong Kong version of Ebay, and have to spend days trying to communicate with them or Ebay to get the transaction cancelled.
I have had this happen now at a increasing rate when trying to purchase Lights , parts or items from Ebay, and began to create a “Do Not Buy From” list of sellers to place on a Black-list.
Have anyone else experienced this issue ?
Nope. I think this policy applies specifically to your address. 
No PO boxes has been around a long time. Sending to a PO box is one of the biggest scams going. There is no traceability with a PO box and scammers have items sent to them, pick them up and claim they never received them. Also scammers stealing ebay IDs will use PO boxes so that the real person owning the ID gets the shaft, while the scammer gets the product. It's been around a lot of years. I do not ship to PO boxes unless I feel like the person is reputable and I don't do it on ebay, because I have beens scammed that way. For people using PO boxes, you need to find someone who has a real address to have the package sent to. Like it or not, it's the dishonest people who ruin it for the honest people.
This year in Canada the federal-funded Postal Service has changed that all items shipped to address here must include the Post Ofice Box number of the address on the shipped item to be accepted now, or it is sent back to the shipper after it arrives to the destination office. The government here is phasing out door-address deliveries for Postal shipments and mail, forcing everyone to eventually get a centeral “Post Office Box with a Number”.
Its another ploy for the corrupt government here to save money, and a fiew hundred Mailmen will loose their jobs, forcing residents to go to the local office to get mail.
believe me i wish it wass just still a regular address, but when beaurocrats want to put more money in their pockets and get rid of more jobs doing it, they will no matter what.
Either way, i have no choice, (As eventually will most canadians living in cities and towns ) will have to only order from shippers whow will ship to P.O boxes.
All the big suppliers like Fasttech, DX, Bangood, IOS, Lightmalls, Wallbuys, and so on will ship to Post Office Box adresses with no problems, its just the fiew isolated, insignificant small Chinese ebay sellers who will not, so its a loss sales to them, i will just buy from somwhere else.
Ebay just needs to change their archaic website coding and add a warning so buyers here in Canada can weed-out those sellers who won’t/can’t ship to them, or a setting that blocks them out of any searching for items from these sellers from the antique Ebay site, especially for those of us forced to use the Ebay.ca (Canadian Buyers) site.
That is a perfect example of that i am refering too !
Canada Post just installed 5 new locations of these in the town i live in. for parcels shipped to these addresses, we recieve a card in the “Box” and then have to go to the centeral Office to pick it up.
If the parcel/package/letter does not have the number of these boxes on it, it gets sent back to the return address, and if there is no return address, it gets probally blown up or sent to the shredder.
- There are probally hundreds of beautful Deft-Xs, Olights, Thrunites, Nitecores, Zebralights, FourSevens, Maglites, etc. being ground up now as we speak, to be melted down and make new Postal Boxes like these for a street near you to be inaccesable by mountains of snow. 
What if you requested a invoice? Would that help? Some sellers seem to prefer to do that. Not sure if the invoice would give shipping instructions. But, yes what a joke. It seems that the listing would have all shipping exceptions noted in the shipping area of the listing. I can also understand not wanting to ship to a “unverified” addy. But, I only sell to the US. I am a shipping dummy and prefer to keep it easy I guess.
From another forum I'm on:
The invoice thing may work, but unsure if ebay sellers will do that option.
I am still waiting for a seller to send me a “Cancel Request” after i have sent 3 messages to them so i can accept the purchase cancelation, if not i have to file a Ebay Resolution case to force it to be cancelled, and usually ends up with them recieving bad marks and negative feedback. My brother has been having an increasing issue with this too.
If Ebay would simply update their aging site with option to bock out non-Post Office Box sellers from searches then there woudl be no problem.
These non-P.O. Box sellers only make up a tiny percentage of the sellers who have more suitable shippng options to buy from.
@DenBarrettSAR...
Either I don't understand your comments about these Canada Post "Superboxes" (community Mailboxes), or you don't understand them. A Canada Post community mailbox (or Superbox) is NOT a PO Box.
My area in Alberta was one of the early adopters to this method of postal service, so I have had a superbox for my mail delivery for over 10 years now. It is nothing like you are describing. Other than the fact that I have to walk down the street to pick up my mail, it is exactly the same as it used to be.
Mail addressing is exactly the same as it used to be. There is no requirement for any "PO box number". Mail sent to you and delivered to your Superbox uses the same addressing scheme as it always did. Your name, address and postal code. Regular letter mail that will fit in your keyed "compartment" is placed in there. If there is a parcel delivered that is too bulky to fit there, it is placed in one of 2 large compartments at the bottom left of the Superbox (refer to the picture above; there are 2 superbox blocks side by side, a double and a triple - each has 2 larger compartments bottom left corner that would fix a parcel up to about a cubic foot in size. If a parcel is delivered for you to the larger compartments, you will find a key in your regular box).
If a parcel is too large to be delivered to either your regular box, or one of the larger boxes, then you will be left with a pickup notice in your box, notifying you that you have to pickup at the main post office in your area. You will also be left a pickup notice if the parcel requires a pickup signature.
I am certainly not an apologist for our postal system nor a proponent of these superboxes, but you may be leaving folks here with the wrong impression about them. There is no "PO Box number" required with them. Just your regular address.
I order and receive parcels constantly from vendors overseas and have all of them sent to my home address, which I pick up at my "superbox". No PO Box number required.