They leave the tab open, and possibly even leave the meter running[1] while you'e on a "break" - so you may end up paying for the time you were not in the cafe.

They leave the tab open, and possibly even leave the meter running[1] while you'e on a "break" - so you may end up paying for the time you were not in the cafe. 1. TFA doesn't say one way or the other, but the fact that they don't accept cash leaves the possibility open