If you're worried about someone bugging you
You take away ALL electronic equipment from them. Or even things that are not electronic but rather mechanical/complex like a Rolex.
Maybe it wasn't a geiger counter, but it sure wasn't to host a bug. There's no way even the dumbest security would allow people into something that shouldn't be recorded with an iPod.
And are you SURE it had a microphone? What for? The iPod Touch models might have since they were basically a cut down iPhone, but what would the rest need with a microphone? They didn't accept voice commands and didn't have any ability to record music, so it seems kind of pointless. Of course you could add one if you wanted to turn it into a bug, but you could add a tiny microphone to a button on your suit and stand a MUCH better chance of getting it by security unnoticed than putting it in an iPod.
Biting the hand that feeds IT
