How many times can a convenience store repent for cashing checks over $1000 without registering as an MSB? We've let a customer sign an affidavit that it was a mistake and he wouldn't do it anymore but now we see where he's deposited several more since then. I know he knows he can't do that, probably was just hoping not to get caught. How do other banks handle? Tell him to register or close his accounts?

Zero times - once you cross the threshold you are an MSB.

I sure thought something came out several years ago where they could repent and say they wouldn't do it anymore but now I can't locate the ruling.

You are probably thinking about this one:

http://www.fincen.gov/fincen_ruling2005-3.pdf

However, this deals with a registered MSB ceasing MSB activities - not an unregistered MSB saying they won't do it again.