I used to travel a lot… often internationally. I’ve only had three “strange” incidents with TSA:
1. TSA randomly picked me for a shoe swab… I’m going to consider that OK.
2. Had to negotiate with the TSA in LV after picking up a pool stick and soft side case there. I put the pool stick in with checked luggage, but the soft sided case was too big. I kept it as a carryon (it was empty), and they said it could be used as a weapon. They let me bring it on anyway.
Funny thing is that my friend went through the same TSA on the same day but was returning to a different state. He bought what basically looked like a wooden little league baseball bat with carvings in it. They let him walk right onto the plane carrying it openly without any questions.
3.TSA at O’Hare had put a “cutout” over the carryon X-Ray machine openning. My carryon was actually smaller than most and fit within airline’s dimensions, but because it was shaped differently (locker bag) it wouldn’t fit through the cutout. They made me empty the bag and mail that luggage to myself in two tiny boxes (they let me bring on the third box). I was actually there for a stopover, and went outside the terminal to see some family who came to say hello.
Internationally things get a little more complicated…
I spent a month flying and taking the train around the UK and EU. I had to to keep some of my luggage in the German airport because they only allowed one checked in luggage and I had two for the trip. They had lockers for this.
When waiting to leave the US for Asia on a redeye, I saw a few younger guys that had just graduated and were celebrating with a trip through Asia. They had bought a $500 bottle of Scotch from the duty free shop, and wanted to bring it with them to celebrate at their destination. The airlines wouldn’t allow them on the plane with the bottle, and they left it unopened on the terminal seats for anyone that wanted it.
When I got to my final destination, I had a second flight a few weeks later within my destination country. They only allowed rechargeable Li ion batteries on carryons, and you were limited to a phone or two and tablet/laptop. My flashlight was a NiMH battery bank from GZ so it wasn’t an issue.
One other time I flew from the US to another Asian country with a US airlines. The flight had an extra stopover not listed on the itinerary (Japan). When I called to ask if I would stop by Japan on the return trip, they said yes, again not listed on the itinerary. They said that it wasn’t listed because “we didn’t have to leave the airplane.” However, both times the Japanes airport’s security required all passengers to leave the airplane and go through their security screening. I wouldn’t have minded so much if I knew about the stopover, as I have a friend in that country I could have visited.
If flying, I won’t take a flashlight onboard that I am not afraid to lose. I’ll usually pack my NiMH battery bank for a light… although I’m thinking of trying a pen light. When driving to different states, I’ll often take my 20 year old SF Defender… although I might change that in the future.