Well, it's like this....
a server will have options of running in two modes, secured & non-secured mode. In secured mode only the client compiled by the server admin can access the server. In non-secured mode any client can access the server. How's that ? admin will use an encryption key while compiling the client & client will use the key to make connection with the secured server.
This way the client still remaining it's OpenSource tag. Only the encryption protocol is varying. (i.e. codes open but connection isnt) And it'll ensure some kinds of fairness when the server is running in secured mode. Because that way a player cant run a client that's not compiled by the admin.
Well, drawback is, it'll increase pressure on the server to make it laggy. But there are ways to make the connection optimized.
If it's implemented, it'll be suicidal to my own portable client. So far I talked against my own client.


.... for the sake of fairness