Just make it so if the player was just spawned, he is nocollided with all props on the map for like 2 seconds.
Though what happens if something causes him to not move - like DDos or DoS lag?
MAGIC: I was pondering this today: Why not take advantage of invisible floors [like those in zs_cosmic_lounge to get to where the nades are], and make spawn points for zombs in the air, or something..... meh that alone has issues to deal with. >_<
ANOTHER trend that is becoming popular in zs_maze is for the zombies to run to that path that takes you to the party room [with the rotating props, and pusning walls], and stay in the spawnpoint at the front of said path trapping humans / killing them.
I mean, t some degree, map design comes into play, but a lot of it is player behavior.