i sense some sarcasm BUT looks like there would be no "scam" going on after all.
i just received the email with the coupon and the coupon specifically states "one coupon per visit, per check".
so don't be so quick to judge.
What dies "one coupon per visit, per check" have to do with signing up with multiple emails (to get multiple "one time" coupons?). That's what we were referring to (because that was your question) - the "scam" is joining the club multiple times by pretending to me different people. Even you know that you were trying to "get away" with something - since you asked if you'd be able to "get away with it".
ETA - I wasn't being sarcastic. It is most likely that they wouldn't know that you were cheating by signing up with multiple email addresses.