you should have it make sure what client is running it is at lest +o also you should really set a channel to use this on but whatever...
also if the server runs anope you could have the chan set to auto voice on join.

you could do:

on !@*:join:#: { 
  mode # +v $nick 
  msg # 12Dont want auto voice? Type -v  If you want voice Type +v 
}
on $@*:TEXT:/^([+-]v)$/S:#: {
  mode # $regml(1) $nick 
  msg # 12You now have been $iif($regml(1) = -v,de) voice. 
}

but to each their own.....