Hand mics in cockpits are a bl**dy menace on the ground, too. The majorityof jammers on Ground are not from vehicles, but from a/c, where someone has slung the mic on the pedestal & then dropped a manual on it.
It seems some silly macho thing with some crews, like a headset's too woosy for them.
Another really irritating thing is people using a mic with the speaker turned up on a different receiver, so there's a huge whistly feedback. It's bad enough having to listen to it when you're in a vehicle, must be really 'orrible for ATC with a headset on!
The Odd One