sv_spectate 0 ignored when client version mismatch the server's
When a client with an old version (i.e. 0.8.2, atm) joins a server and it's version is older than minimum required version, they state in spectate mode unable to join.
This is fine, except when a server has sv_spectate 0
which should disable spectate regardless of client version.
I think the best option in this case is to just kick the player out of the server, with an 'unsuported version' message or similar.
Failing to do so is just an easy exploit to spectate on servers with spectate disabled.