It may be against the terms of the merchant's agreement, but locally in eastern Canada it's quite common (for both debit and credit transactions), and (although

It may be against the terms of the merchant's agreement, but locally in eastern Canada it's quite common (for both debit and credit transactions), and (although I don't follow the issue closely) I've never heard of a lawsuit brought forth over it. I'm sure the CC companies would be up in arms if it were a national chain of some kind, but the little Mom'n'Pop restaurants and convenience stores seem to fly under the radar, even if that category may be large in aggregate.