I suggested that system to avoid cheat players, as well, but there's actually a big problem with it.
I can't speak for PSN, but on Xbox Live you can exhaust your available avoids quite quickly. I hit the
maximum number of avoids after doing this for only a few weeks. Even most Xbox Live staff do not know
there is a limit, and I spent two months in their troubleshooting qeue before someone finally found
Needless to say, using that method dramatically affects your ability play multiplayer and co-op in other
games. Therefore, I actually recommend you don't use this method at great length. It will work for a
limited time, but after that, any "avoided players" added beyond the maximum will reset every time you
log in to Xbox Live.
I have no suggestions as far as what to do, instead. In my case, I simply stopped playing Co-op.
-Jeremiah the 12th Level Geek