There are plenty of restaurants in Belfast that let you bring your own beer. But their business model is clearly that they are a restaurant - and thats where they make their money.
That said, if someone had told me that there was a place where I could bring my own booze, pay a couple of quid for the privelige, and then drink away for the night, I would have immediately said that it would be abused by students and the like. But no, seems to work fine!