I play in the midfield until they start camping. Then I wait for a while to see if they will come back out after getting a decent base set up. If they don't, then merciless baseraping it is. I'm not going to wait 20 mins waiting for them to come to me...
it's terrible, I hate to see it happen especially when the other team just starts leaving and it boils down to one or two players, and I hate to have it happen to me too.
There should be something in place for this but I guess late joining can't fix everything.
Also it always takes a couple of respawns to realize it's happening haha