This is a phrase heard quite commonly in the rougher bars in the UK. Basically, if customers misbehave, have misbehaved in the past or seem likely to misbehave the owner of a business, usually but not necessarily a pub, is entitled to refuse to serve them. People fighting, arguing, making racist or homphobic comments, causing damage or getting so drunk they puke on the floor can be barred. I think most people would agree that this is a reasonable reaction for a business owner with the best interests of his/her other customers at heart. However, it would not be reasonable for the pub owner to come across to your table and say "This is a sport pub, you were talking about books. Get out." Gr worse still "Get out, you're not wearing football strip and you look like you might talk about poetry".
But isn't that more or less what Paypal is doing with its ban on certain controversial subjects? J S Wayne has explained why this is a very bad thing here but I would like to know what Paypal's criteria are and how they are applied. Who, in other words, makes the decision that a book, or an author, has to be banned? Are Paypal going to employ readers to skim novels electronically looking for certain triggery keywords? Or are they hoping the publishing industry will self regulate by choosing not to publish books with 'questionable' content? Or are they hoping that authors will restrict themselves to the straight and narrow?
Fat chance, Paypal.