All these laws are well-known. You hear radio ads for special offers that say things like 'not in rhode island' in the gabbleprint at the end. Every supermarket clip-sheet or flyer has lists of the exceptions at the bottom.
Are we to understand that Groupon had not built this in before cutting code? never mind the IPO this should be in the requirements spec.
If they were trading willy-nilly I'd be inclined to mark them 'avoid' myself. Surely not? in the domain of the landshark?