Lost ball -- probably played by another

[Groucho Valentine]

A very similar thing happened to me in my club championship last year. I hooked a drive on a very short par 4 (only 295 yards) into the adjacent fairway, and somebody picked it up while they were playing that hole. Everyone in my group CLEARLY saw the ball land and come to rest in that fairway. The hole is situated in a way where i actually had a perfect angle to the hole even from the adjacent fairway. 

After we didn't find the ball we figured the group playing the hole picked up the ball while they were playing through. I ended up playing two balls that hole - one where everyone in the group agreed my original shot came to rest, and i replayed another from the tee box. I asked the group if they picked up my ball when i went back to replay from the tee box and they all denied it. (Someone in that group lifted it)

I made a birdie on the dropped ball from the fairway and a double on the replay with the penalty. With the three i would have ended up winning gross by 3 strokes - with the penalty, i was in a three hole playoff. The committee there questioned everyone involved decided the group picked up my ball. They gave me the birdie score on the hole, which awarded me the club championship. The other players in my group had no issue with it, even the guy i would have ended up in the playoff with. I don't know if was the right call in the letter of the rule, but it felt like justice done.  

Edited June 24, 2016 by Groucho Valentine