No worries (at least at LAX International). I have carried arms in my backpack many times but allen wrenches get flagged half the time. On our latest trip to Indonesia, the screening guy asked was my housing Nauticam (it isn't) just from looking at the x-rays.
I thought I posted this, perhaps I was dreaming. None of the UW guys release detailed numbers. Ikelite is reported at sales between 5 and 10M per year with 200 or so employees by sites that look at registration of companies. The camera guys are easy to get numbers for, the housing guys are really secretive and since they are private they give up almost no info.
I would slightly disagree that most rechargeable batteries you can buy are low internal discharge (eneloop type), there are tons of regular NIMH batteries out there. In my hands with a computerized battery discharge tester regular eneloops did better than the eneloop pro batteries for strobes (not for constant current devices like torches or camera backs).