client console commands can't be detected by HLDS, i tried something similar to block the fullupdate flood, with a bool set on true for the first full update, and the bool set to false on command stop, from the demo recording, but, the command stop can't be catched, valve did this since protocol 48. But lucky me i founded that time a different code here in forums to limit the fullupdate usage.
The answer is no, you can't hook the setinfo command. Tell the exploit on
ConnorMcLeod of other experienced coder, and maybe they can find a solution for your problem.