I sincerely doubt that consumers love being directed to a sign up page before they see deals. There are easy ways of getting to the deals without signing up but as far as being user friendly, that it's not.
I'm sure this is not helping the quality score of their campaigns but as Leosghost indicated, both Groupon and Livinsocial spend millions in AdWords and one could argue it's part of their business to know the city you are in or want to see deals for so they can offer you relevant content. AdWords policies are mostly guidelines and not always enforced, depending on the situation and the severity. I wouldn't expect Google taking any action on this anytime soon.