Someone you don't like accidently drops something, and you pick it up... what now?

[Ashimar]

Lets just put it this way. Ranger drops his Wurmslayer on the ground, accidently while swapping his weapons and doesn't realize its gone until 5 minutes later when its not in his inventory.

Tank#1 picks it up off the ground before Ranger see's it and doesn't say anything.

So if i decide to be a P99 Douchebag, and keep the weapon without telling him,
because he was a dick to me before...
(im sure if he petitions the GM can see that it was picked up off the ground)

can you be banned for this offense?