Once everyone at a table has their main, and there's nothing more for them to order, a server with spare time prints the check and leaves it on the table in a dark folder while they eat.
When the whole table has finished, guests paying cash leave it with the check and go straight away, without waiting for anyone. Card payers still need a server, who comes just to collect the cards, run them at the register and bring them back.
Nobody pays before the whole table has finished, as before.
It only happens in real spare time: a server idle for 10 seconds with no other front-of-house job waiting. Earlier versions of this sent a server whenever one was free; the trip to the register and the table can't be broken off when the next party walks in, and in testing that cost about 6% of guests served.
Later, with desserts, the check will wait until dessert has been ordered or declined.
CHEF!