I like the idea, but I think the ATM's at best should be spawned outside the venue, and you would be able to link your business to the ATM for it to become operational. The reason for this is because ICly you wouldn't be allowed to have this due to safe gambling laws and what not, you could easily be sued if someone loses ALL of their money in your venue, because you gave them direct means to do so.
But definitely supporting ATM's outside and being able to link your business to it.