I believe that Nando's does the same thing. They always take the table number after asking you if everything's okay. Interestingly, just as in technical system

I believe that Nando's does the same thing. They always take the table number after asking you if everything's okay. Interestingly, just as in technical systems, problems arise from trying to keep the state consistent between two separate systems (the table and the kitchen, in this case). At the table, the 'Waiting for Food' state is indicated by the presence of the table number, but in the kitchen, this state is indicated by the presence of a slip of paper with your order on it. In my experience, it's quite common for the kitchen to misplace your order slip, so the two states get out of sync. To the kitchen, it looks like you've got your food (or you don't exist), but at the table, there's no food so no one checks on you.