Spawnfragging rarely happens (if at all) in Quake, because the game not only checks wether the spawnpoint is clear, but also spawns you at a point where no enemy is in the immediate area, if possible (UT even checks line of sight to spawn you only when you are out of other players view or at quite some distance to them - if possible that is!)
As I noted before a similar check should definitely be implemented.
A telefrag is something different, though, as it occurs, when 2 players use a teleporter in rapid succession - I never saw that happen in IL2
