Sounds good except that would be like DDoSing a server because of the constant packet sending.
Sending a Torque ping request involves 2 packets, 6 bytes each. A packet travels to the server, and comes back. A mod like this could pick an interval like 1 second.
Packets sent to a connected client (includes in-game and the datablock/download phases) are 128 bytes each, and there are 32 packets sent per second per client.
There is no problem in making a mod, so long as the server checks player count before authentication (the way it should be).