sounds like a lot of discussion here can be boiled down to what has already been stated:
leave yourself extra time for the unexpected. I have flown dozens of times, pre-and post 9/11 with a rig, and my homemade li-ion batteries from 2002 that im still using are a bit on the sketchy-looking side.
i always make sure i have enough battery to power the rig, to turn the lights on and demo that it actually is a battery and a thing with lights.
usually batteries are :
b. cheap and replaceable (relative to other electronics)
so i try to check em
I took my gear bag out of my backpack for the first time last weekend, and didnt even get a hand-search, as they were 'less confused' when it came down the pipe