In their eyes, it doesn't matter what led to the mistake happening; everyone else is at fault but them. Even if you only imply that they should take responsibility for their own actions, they will act as if you wronged them and their entire family. It's impossible to win an argument with them.
The very least you can do is not give in to their demands. They can act like their mistakes are yours all they want, but that doesn't mean they will get what they are after. When it comes to the service industry, there are plenty of ways to teach people like this that they can't always get away with blaming other people for their faults.
There is a lot this customer refuses to come to terms with; his mistake is one among many things he decided to blame on the hotel that was unable to accept him as a guest. It all started when he arrived at the front desk and discovered his booking did not appear in the system. After some digging, the front desk clerk found that a booking had been made in the name of this guy, on the same date, but to a year ago.
Apparently, the guy did not notice the wrong date, but not only that, he didn't check his emails for confirmation, didn't notice the charge made when he failed to show up for the booking last year, and didn't think to check that his reservation still existed after he made it so long ago. Even though all of these were actions he failed to do, he still blamed the hotel for not informing him of the error.
Since the hotel was fully booked, they were unable to give the guy a room, which, after all of his claims and accusations, we're sure they didn't mind. The guy, who clearly had issues with taking responsibility, doesn't sound like the best customer to serve…