As others have pointed out, we were always taught that just before the end the message would change from "last chance" to "too late". We would be like Jeremiah delivering a message of doom. I kind of looked forward to that. Seemed like it would be a lot more fun than trying to talk some asshole in a big house with a Cadillac in the driveway into a free home Bible study. Just ring the bell and say "You're toast, M----r F----r, and don't start pleading! It's too damn late!" (All the while checking out his crib you might want for yourself after the big A.)
But, seriously. I can't see the WT telling everyone the door has been shut and sealed. That would be slow suicide for the Org.