Maybe a Stock Bug With Keys?

We (our players) noticed that on locked doors with key num -1 you can unlock those doors by having a corpse (vnum -1) in your inventory.

I wanted to check if this is true for the stock code, I imagine that's not an intended way to open those particular doors.

If that is indeed a mistake, the problem is in act.movement.c around line 460 (has_key() function).

You can plop in something like this on top of that function:
*note this assumes corpses are actually vnum -1 in your game