Good fold. 👍

In this spot, there is always that slim chance that the straightforward player is spazzing out, doing something that's very out of character, pulling some weird bluff or semi-bluff with players behind after sitting for hours without a hand. But most of the time, even if you suspect that's the case, it's better to fold, because you'll generally get a much safer chance to take that player's money in a later hand.

Well played; even many decent players would have called the checkraise on the flop out of curiosity, losing a little more with a chance to lose a lot more, if a killcard drops.