The admin orb is a camera. It does not collide.
You might get some results using a trigger zone, if cameras can be detected entering and exiting.
Either way, you must also take into account /warp, destructo wand, and the fact that needing a brick to limit admins means that you choose bad admins. Try solvintg the cause of the problem rather than getting a partial solution that probably would qualify as a crap-on.