You know what, Martyn, I just re-read your plight, and I have to say two
things:
1) People who are that paranoid are usually guilty of it themselves. If
they weren't exploiting, they were probably up to something just as bad.
2) As has been supported by GMs, Guides, and the programming of the game:
If someone leaves a corpse long enough for someone else to loot it, it's
FAIR GAME. Their own darn fault.
3) The fact that you wanted to stay around and get a mask should have been
clue enough, but obviously they didn't get it.

The simple explanation for what happened is that occasionally, if a mob has
no loot, the corpse will vanish very quickly after dropping. There never
was a mask, and they are idiots for accusing you. Do what I do. Ignore them.

Talies the Wanderer