Figured I'd write up a feature vote for this since I've already been spending some time trying to track down what's going on.
I've narrowed the problem down to this:
Sometimes players are hidden because of the PVS (potential visibility set) system -- they're completely out of view, so there's no point wasting network updates on them. A lot of sounds use the entity for the position to emit the sound from, though. If the sound is in the PHS (potentially hearable set), but the entity it's emitted from is outside of the PVS, the sound will emit from the last known position.
The most common place I've seen this happen is in shazam22. If you kill somebody in your base, then the next round starts, you'll hear sounds of equipment being picked up from the location that player was killed.
