Poor business practices
I was bumped from a flight because it was oversold and was given a United Airlines voucher to spend the night at the Hilton on-site at O'Hare. 
When I gave the voucher to the front desk clerk, he frowned at it as if he had never seen one - this hotel is IN the airport. He proceeded to tell me that with the voucher I could have a room that backed up to the elevator shaft and instead of a normal bed had a "Murphy Bed" which folded down from the wall. Every gesture and sound he made indicated that this room was terrible and I did not want it. 
He then pointed at a digital picture frame which featured a slideshow of pictures of a very nice room. How lucky for me, he offered to "do me the favor" of upgrading me to that room for an additional charge. It CLEARLY was a speech he had given many, many times to people who had the misfortune of being stranded at the airport for the night. 
I told him to give me the voucher back and that I would go back to United and then to another hotel. I did not want to take the elevator shaft room with the fold down bed. Somehow, miraculously a normal room was suddenly available at no extra charge.
I couldn't believe that I was at a Hilton, which I know to be a decent hotel chain, but was being swindled and lied to. This hotel seems to systematically prey on travelers who are stranded. Why do accept the vouchers at all if they don't cover a normal hotel room? 
The hotel itself is nothing to be proud of. It's worn and dated and generally not up to the standards you'd expect from a Hilton. Everything had an upcharge - internet, gym, etc were not included.