It happens as they are best items to stole. It happened with me once.
This story went round and round in the 80's.
Norfork, a bad accident in one of the tunnels. A woman wearing a nurse suit jumped out of her car and ran to help a passenger in a wrecked car. The male was all wedged against the dash board. Waiting for EMT she asked him if he was 'Holding' he replied he was and told her where his drugs were. She told him she would meet him at the hospital to return them.
Poof, last he saw of her. After he got out of the hospital in a couple of weeks he went to the POLICE asking them to find her.