Like PP said, they cut it off much earlier than that... around 5. They don't want people with an ADR time at 6:30 finishing their dinner at 8 (perfect timing to catch the Boo-to-You parade). If you are attending the party, you can book for 6:30.
They will ask you when you book ADRs but anyone can lie and say yes, but they may very well check for your tickets at check-in to the podium.