This is taken from the reservation page when you try to reserve a room

"We reserve the right to cancel or modify reservations where it appears that a customer has engaged in fraudulent or inappropriate activity or under other circumstances where it appears that the reservations contain or resulted from a mistake or error."

This is excerpted from the site usage agreement located at the bottom of every page:

"We also reserve the right to refuse service, terminate accounts, remove or edit content or cancel orders in our sole and absolute discretion."

This is an excerpt from the HHonors T an C found on the bottom of the HHonors homepage:

"9. Hilton HHonors Worldwide, LLC, reserves the right to discontinue HHonors membership for any Member who appears to be using the Program in a manner inconsistent with the Terms and Conditions or intent of the Program or any portion of the Program, including, but not limited to, Reward redemption or Certificate use. Hilton HHonors Worldwide, LLC, also reserves the right to discontinue membership for any Member who acts in a manner inconsistent with local or federal laws, statutes or ordinances or if there are reasonable grounds for suspecting fraud, theft, or dishonesty in connection with the account. Discontinued membership may result in the loss of all accumulated points and the cancellation of HHonors Certificates, benefits and privileges. In addition to discontinuance of HHonors membership, Hilton HHonors Worldwide, LLC, shall have the right to take appropriate administrative and/or legal action, including criminal prosecution, as it deems necessary in its sole discretion."