Problem with reserved slots is that it takes it from the total number allowed. So if you reserve 2, only 30 people other than those two named can join. If those 2 are away on vacation, you're now running a 30 man server.

The way it SHOULD work is to allow 32, and if a reserved player shows up, it boots a non-reserved player at random (or the lowest scoring guy) to make room.

In the meantime, an admin has to do the booting himself using the console tool. Inconvenient, but doable.