Rings get lost....the finders are either honorable and try to find the owner (its' really not that hard), or not honorable and try to cash in. (Often the honorable person gets rewarded).
Funny lost ring story ...My P3 crew landed at an AFB for fuel in the middle of the night back in the late 80's. As we were taxiing out , my Nav asks what base we are at (that in itself was funny,,,the Nav not knowing where we were, but in his defense we were flying airways so the Nav was sleeping when we decided to get gas and landed). When I told him, he admitted that he had left his ring on the bathroom sink in Base Ops. Fortunately for him, 4 of the 5 Officers on the Crew were Naval Academy grads (and all junior officers), so without question, we taxied back (a long way in the middle of the night), shut down and retrieved his ring. I'm sure the folks in the Tower got a kick out that (and told plenty of Ringknocker jokes)