I keep everything, and never speak of it.

I drop the bag including all its contents back to the ground, then walk away.

I take the better piece of gear, drop the bag and its remaining contents back to the ground, and walk away.

I contact the owner (/ooc, etc.), verify ownership, and return all items... except the one piece of gear I secretly kept.

I contact the owner, verify ownership, and hold all of the items hostage for a monetary "reward".

I contact the owner, verify ownership, and return all the items to their rightful owner without conditions, or expectation of reward.