Well tedunangst's point, which is worth considering, is that the customers who hang around will bypass the whole raised price scheme by ordering an actual meal

Well tedunangst's point, which is worth considering, is that the customers who hang around will bypass the whole raised price scheme by ordering an actual meal and getting the discounted price. But that's still avoidable by having the discount structured so that you just can't get a Turkish coffee without paying some minimum amount, determined by trial and error to make it nonviable for retirees to purchase and then sit around all day. With that scheme, however, it becomes more complicated to work out what price makes it worth it for them to actually just sit around, because you also have to factor in the cost of the food they're wasting.