I know people who have done that and there is no problem. When you arrive at the destination airport just let the rep know you wont be staying at the accomodation or you may delay the coach while they wait for you!
If you are planning to go to travel for a short sightseeing trip, finding a cheap package tour might be a good idea. Thanks for the information here - I was really struggling to get a travel information but your site shows clearly and easily how to do this.! ------------- http://www.flylink.ca
Read the contract, there was an article in The Sunday Times travel a few years ago about some companies requiring you to check into the accomodation to complete the contract and if you didn't check in cancelling the return flights. I seem to remember them recommending that you check in and then immediately checking out to satisfy these requirements.