Not Travelocity, but I have skipped the hotel with United Vacations and it didn't make a difference.

I actually went to the hotel first and handed them the cert. I told them that I didn't want to stay as I didn't like the hotel. They didn't seem to care one bit and didn't even want the voucher for the room. I guess either way they get paid.

The second time, I didn't bother going to the hotel at all, nor on subsequent trips.