They probably won't catch you at first but... this is one of the worst things you can do in DIRECTV's opinion, short of committing out-and-out fraud. It's essentially like bringing in a receiver from home. They take this very seriously and if you are caught you should expect to hear some harsh words coming from your DIRECTV people.
Why is this such a problem? It all has to do with the idea of "public viewing." If you put a receiver in your bar you are showing the programming to the general public the pricing structure is very different.
When you put in a receiver in a public area, it's priced according to the fire code occupancy of the area. This is done so that royalties can be collected and sent back to the companies that make the programs. It's all part of complex legal agreements put in place between DIRECTV and those content providers. If DIRECTV doesn't honor those agreements then they can be fined a lot of money, so they make sure that the individual customers are doing their part.
It's also true that if you have a DIRECTV Residential Experience system, you can't take one of the receivers from a room and put it in the hotel bar.
The bottom line here is that putting DIRECTV service in the bar is more expensive, that's true, but it's more expensive for a reason and if you try to avoid that there can be some serious problems.