The fact that Groupon has to engage in such tactictss goes to show that they are hitting the limits.
IMO they were idiots not to take the GOOG offer. It was a huge one and I doubt they will ever reach that valuation again. Discounts like gropon never work I don't know many people who have give n the business a consistenty repeat busiinessafter going there first using a groupon.
As stated, it would seem to run counter to FTC section 233:
http://www.ftc.gov/bcp/guides/decptprc.htm