Last time I flew out of Coz in March, I had my carry-on full of all my heavy & expensive items. Can light(Li battery), Computers, backup lights(all lithium batteries), explorer reels, dive lead, etc. When I saw my bag go through the X-ray machine, it looked like a large black blob. I knew what was in it and had a hard time discerning what was what. Obviously I got pulled aside for a spot check, but it was busy so there was a long line. I was worried that they'd give me a hard time with my stuff until an obnoxious couple of American tourists decided to make a scene. Suddenly the line for spot checks got a lot shorter as we got sent on our way while the obnoxious ones got some extra scrutiny.
I have no doubt that I would have had to argue to save my dive batteries, but sometimes it pays to put up with the obnoxious tourists.