parabellum, copy Rainboe;
I can't disagree with your comment re craftiness and smoking on board - seen it, had the warnings in the cockpit. I do know that along with smoke detectors, lav waste bins do have automatic fire extinguishing equipment in the waste bin, (no cockpit indications of discharge).
Unless proof for prosecution is the intent, I can't say that I see the effectivenes of lav video cameras however, and if crafty addicts can cover smoke detectors, they can vaseline lenses too.
Someone hit on the key item - security is a PITA for most and most complain of its ineffectiveness, (not saying it's actually ineffective - we don't know...), so let's make it seen to be meaningful as it levels the playing field - smoking materials are far more dangerous than 99.99% of all items now taken away at security. You can't take bottled water onto an airplane but you can take a lighter. And why stop there?,.... Confiscate all smoking materials - The TSA don't care about the huge losses incurred by passengers from tossing all those fancy over-100ml perfume/cologne bottles and the expensive wines you didn't want to pack for fear of breakage...so just take away the cigarettes, lighters and other smokable materials at the same time. It's a smoke-free society, so the sympathy is there to deal with smokers in the same tough way that security deals with smugglers of bottled water. I think passenger advocacy groups would support that before they'd support lav cameras...