It depends on the show. For shows that use "and now everyone's back!" twists, I suspect the entire block is filmed in advance, so I suspect any time a player makes a comment that might indicate what time it really is, it gets edited around.

Syndicated shows probably also have a block or two taped in advance - although in those cases, the host is often aware of what the air date is so they can make timely comments about the time of the year. The available cushion may fluctuate based on the game and whether bad things happen, like sick hosts or competitors, but I suspect there's some ideal amount of lead time wanted.