Maybe its my general paranoia ("just because you're paranoid doesn't mean they aren't out to get you") but someone who is trusted and informed today could be untrusted tomorrow -- and unless you track who has what and/or practice proper credential rotation its a risk.

Just like sharing keys to your house with a neighbor has the potential to bite you in the butt if they go insane and you don't retrieve the key or they keep a copy for themselves (incidentally that's the second reason my house doesn't use physical keys )