they can do anything ......you're the first person I've ever heard of that has first hand info regarding customs caring.....they find mine every time cuz I have several w batteries and they're large.....many many times this has happened at both suvarnabhumi and hkt and customs checks it out and puts it right back in the bag....guess I'm .lucky
they are ubiquitous and essential for people that need a recharge but don't have access to, or time to use, a USB port...I've used both since 2011 and the battery type is more reliable