uhm if I may, cant you also edit the echoes params to assign who can see them?
unless however you want to do away with it completely, but if your intention is to make so that admins cant see YOUR ulx commands, then...
Example: SuperAdmin BOB suspects a cheatsiedoodles, (silent) bob is spectating cheatsiedoodle.
Admin JOE suspects BOB of cheatsies, "BOB IS SPECTATING CHEATSIEDOODLES"
"SHH JOE, I THINK HE'S A CHEATSIEDOODLE"
(insert continud confusion here)
you may want to just edit the permissions in the !menu and uncheck all the echoes you wish to disallow, group admin gets them by default rather the file...
but I mean that in the most respectful way possible, somebody else could stumble upon this thread with the intention I just mentioned and help them out instead. as long as it benefits somebody in the long run.