What happens is, you have a policy, and you know it’s being infringed but you don’t care to investigate further, then you have a few complaints, word gets round, custom drops off, you get a reputation for being a dodgy business, people avoid your business, because if you don’t care about this law, what else don’t you care about? Fire regulations? Health and safety? the police investigate any reported assaults, harrasments or voyeurism, and if your business needs a licence to operate (alcohol or live music etc) it becomes difficult in many more ways.
it’s a bit like underage alcohol sales.