Apparently, to you, anything that requires even an iota of thought is "rocket surgery". A business refusing to serve someone has to be reasonable and justifiable. The only "right to refuse" they have are Individuals or groups who are causing trouble or being disruptive may be asked to leave, while restaurants or other businesses with a capacity limit can turn away customers to prevent this limit from being exceeded. Businesses can also refuse service to those who come in just before closing time or to those who are not making any purchases during their visit. There are various other examples – the key thing to note is that in each example, the decision to refuse service is not arbitrary or based upon an individual’s specific characteristics. Declining to serve someone has to be reasonable and justifiable. If customers are not properly dressed, you can ask that they leave, but if a person is wearing reasonable religious apparel and you dislike their beliefs, you can’t use that as an excuse to send them on their way. If there are safety concerns, or someone is harassing your staff members, then a business can refuse service. Likewise, if the way a person is dressed violates health codes, you cannot legally serve them, and if their clothing does not match your business’ clear standards – if someone wears jeans to a black tie dinner, for example – then you have a clear and justified reason for your refusal. Again, you have no fucking clue as to what you're talking about.