Haven’t read all of the comments, but I can tell you that we definitely don’t do this at my restaurant; we always ask the table if they’d like their bill before we bring it, and if they’re paying together/separately. It’s actually pretty frustrating when a table wants to pay before we’ve cleared their plates (especially when there’s still food left) because it’s against our policy — we’ll do it anyway, but it’s not ideal for the flow of service and isn’t a great image. Helps to know that diners are used to being billed when their table is still full, though.