It might be nice to have a flag of the segment properties the mission design could set that would disallow a player from joining after that point. The mission designer should know what parts should be fun and what parts wouldn't be worth joining if you've already missed everything else.
You do get asked something "There are 8 minutes left of this mission. Do you want to join?"
How the heck should a player know? Is it 8 minutes left out of a 10 minute mission? Is it 8 minutes left out of a 30 minute mission? Have they already hit their target? Are they on their way home, but the designer has a surprise for them once they start the landing pattern? Or is all the fun over, and it is just a boring 8 minute flight back to base in a straight line and a landing pattern with never a red icon seen?
You shouldn't offer the player an option, when they can't possibly have enough information to choose, that will just result in an unenjoyable, dull user experience.
Yeah, I've had some of those.
