I don't know if that's a known glitch. But it's very easy:
1) Go to the "Maps" directory in your war rock folder and then go into the map directory from the map which you wish to modify
2) Open "ControlPointTemplate.dat" with an editor
3) Find the lines with "ControlPoint.Team" and change the numbers behind them to "0"
4) Now it's done. In the map you've chosen you can spawn on each spawn point as long as they aren't taken. Yes, also the spawn point of the enemy.
I hope it's useful...
Edit: I found a second very useful glitch:
1) The same like the first one
2) Open the "StaticObject.dat" and delete all text in it.
3) Now there aren't buildings on the map anymore and you can shoot through the whole map and the terrain textures are still there, so you don't get called as a cheater