U know what dude?
Well, call it a coincidence but I was asking myself the very same question today @ 13.00.
I was thinking to keep the flags locked + AI there invulnerable, not to upset the game balance and give for free some stuff at base such as attack choppers, temporary weaponary and so on and let the guys spawn at a dummy area to have some fun and/or experience.
When players reach a certain number on both sides the game will delete all the free stuff perviously given and game can start.
It may sound stupid but will help players to stay and wait for others.
Something like, anyway.
"When taking part in a discussion, the most difficult thing is not defending your opinion, but knowing what it is in the first place." André Maurois