What I wanted to say was that the logic needs to be a bit more tweaked than plainly: PS covered when ringing = answer the call.
There'd be more logical steps (PS status) to check before automatic answering would work as expected.

1. Phone in pocket = PS covered when call arrives = don't answer automatically
2. Phone out of pocket = PS uncovered
3. Phone to ear = PS covered = answer call

BTW denying the call would probably work with the accelerometer, not with the proximity sensor, so I guess no interference.

Ahh, and in my case there is no annoying crazy-frog-ringtone that could damage my ear-dums ;-)