[1800GAMBLER]

This is a god god god god god god god awful fold. Simple logic shows how it's an awful fold:

Here's the cases, you are currently getting 3:1 on a (at worse) 5:1 shot so all he has to do is to bet/call the feckin' turn and you are getting your odds.

So for you to fold he must never ever ever ever ever pay you off for 1BB. Ok so if ever time you call the flop he folds the turn your bluffing equity is 100% and you pick up the flop on the turn every single time.

So you are either getting the implied odds or bluffing equity.

edit: TStoneMBD said it better than me.

edit 2: amazing how many replies do not understand equity or how your outs 'double' the times he checks the turn.