Imagine you are a licensee. It’s a bitterly cold day. Someone comes in your pub on their own and sits down at a table reading a free newspaper. This person isn’t an obvious loon, but may possibly be something of an eccentric. They show no sign of buying a drink or ordering food. The pub isn’t sufficiently busy that they’re depriving someone else of a seat. How long do you wait before speaking to them, maybe asking whether they would like a drink? Or would you just leave well alone if they’re doing no harm and only intervene if they started doing it regularly?
On a related note, over the years I’ve noticed a distinct shift in pub behaviour. In pubs where food is ordered at the bar, in the past groups would come in, get their drinks, sit down and then peruse the menu. Now, increasingly, they sit down at a table, peruse the menu and then go up and order food and drinks at the same time.