What more evidence do you need? They shoot 64 then turn around and shoot a 38, which when being figured for you average is doubled to a 76. That 38 wasn't 2 or 3 rounds after he shot the 64, it was the very next round.
And yes I did shoot a 59, in an UNLIMITED tournament, this player shot this round in a Single Play tournament. The tourney I shot 59, majorly attributed to a RARE DOUBLE EAGLE, I posted more than 11 scores all of them UNDER PAR. Not to mention the 30 or so times I started and ended a round because it wasn't going good for me. Ending a bad round and only finishing rounds below par is exactly opposite of what a sandbagger does! So if people want to call me a sandbagger, I would just simply laugh, because they obviously do not know the meaning.
And as far as that player declining the prize, maybe a guilty conscience? I don't know. If I had won that tournament and felt like I deserved it, I would have accepted it.