I just posted not long ago. I went to
http://www.hilton.com/en/hi/promotions/Hilton_Grand_Vacations_Club and called the customer service number. After being transferred a couple of times I got a hold of the telemarketing manager for Hilton. It seems if you stay at one of their hotels they reserve the right to contact you for further business. As it was explained to me they consider you a "prior business contact" and therefore are allowed to call you without regard to the do not call list. I could not get an internal number to call, but they said they would expedite the removal of my phone number. I further explained to them that many of us that have been receiving these calls would be very hesitant to stay at a Hilton hotel again. I also explained how annoying it was to get called 2 to 4 times a day without anyone answering. Here are their brands:
Hilton
Conrad Hotels & Resorts
Doubletree
Embassy Suites
Hampton Hotels
Hilton Garden Inn
Hilton Grand Vacations
Hilton HHonors
Homewood Suites
The Waldorf=Astoria Collection
The only thing I can advise is if you stay at one of these hotels make sure you deny their right to call you afterwards. As for me I will probably do the easier thing and just avoid staying at their hotels in the future. I previously stayed at a Hampton Inn.