I think you've been had.
a) your crash script didn't crash anything I tried. (since I was curious, having never heard of this, I tried some things)
b) forcechanged is needed for clients to switch force powers.
c) forcepowers is most likely parsed by the client before it is sent to the server.
d) there is no way to disable specific commands on clients in JK2.
then u dont play it very often xD
most servers have disable it and course u can disable some cmds
some servers have cheats on but u cant use cheats like god give notarget ect coz they disable this cmds
it isnt impossible....