It depends on how the merchant treats a Groupon customer. They may make up for the customer acquisition cost by offering less (hurtful to them) discounts in the future. Take this spa for example, they did a follow up for Groupon customers offering the same 50% deal, but this time they kept Groupon's share:
And I think we can all agree that hurts Groupon in the longterm. So.... doesn't seem like it depends at all, regardless people are trying to avoid using Groupon.
http://feefighters.com/blog/who-groupon-benefits-the-contrac...