I like this idea. You also might consider checking if they're typing your channel name or others.

Code:
 on @*:TEXT:*:#: {
  if ($nick !isop $chan) && ($wildtok($strip($1-),#*,0,32)) && ($matchtok($strip($1-),$(#, ),1,32) != $chan) {
    .msg $chan No advertise $nick !
  }
}