Interesting thread. I'll be preaching to the choir here, for the most part, but OP asked...
Like any powerful tool, high-performance flashlights can be misused.
Nighttime in the country. Bubba has a beer in him. Bubba sez, "Hey y'all, watch this"
Or, mean kid/delinquent/bad seed has mommy's kewl new light, prowling the dimly-lit suburbs. Kid sez to companion, "Wanna see somethin' cool?".
Or, someone with truly nefarious intent knows exactly what he's doing.
Meanwhile, tired soccer mom/corporate CFo/CountyJudge is finally on their way home with the kids in the vehicle. Dim dashboard lighting and headlights reflecting from the road have their pupils well dilated for max night vision. They're instantly flash-blinded; hit squarely in the face by said bubba's flashlight brilliance or, worse, by stupid punks strobe. Bubba's idiocy results in simple flash blind. Punk kid's stupidity results in same, plus the disorienting effect of strobe. Nefarious criminal keeps the beam aimed precisely at the windshield, preventing any clear view of the road. Either way, worst case is driver/passenger(s) have a very bad night. They probably live. Or not.
Like any powerful object, some measure of responsible intelligence is implied in it's use
In grade school we were evaluated and graded on how well we followed directions. Safety documentation is widely available for LiIon cells. Every loose cell sold to consumers should come with safety instructions, IMHO.
When all else fails, read the directions. Think.
Seem to me, devices that don't have reverse polarity protection have a fatal design flaw. Pun intended.
Mistakes happen. The uninformed do get their hands on items of which they only know the basics. "Uhhh... this looks kinda like a battery. Weird lookin' one. Odd place fer a switch, here on the end of this fancy flashlight. Look, it unscrews! I think this weird battery will fit. Let's see if it works!".
We can use our imagination from here.
If we keep buying items that don't have the simple feature of reverse polarity protection, manufacturers have no incentive to remove that flaw.
I'm new to the HiPo light scene. It looks to me from a newbie's perspective that we're in a golden age of handheld lighting. Wish I had answers. It'll only take a few sensationalized news stories re: those "assault lights" before things are legislated to our detriment.
"Those weird batteries are dangerous. They don't even sell them a drug stores. The government should get involved".
"No one needs more than 100 lumens!"
"Those scary black flashlights will blow up! Think of the chirren!!".
"Ban them, before they start making bump-switches and shoulder things that go up!!!".
"Common sense flashlight laws!!!!".