Hi.
What game? And what part from the SMAC bypassed that player?
If CS:S and autotrigger bypass, the solution are very easy.
If you running a normal server (not surf, not zombie) you can setting these values in your server.cfg and the speedhack, bunny hop will be ended.
If he try using that shit, you will see. Thats all.
sv_enablebunnyhopping 0
sv_airaccelerate 1
sv_max_usercmd_future_ticks 1