You do have a point, unless I misunderstood Online's suggestion. Currently, $identifiers are allowed to start a line in a script, but their return value will be used as a command. So, fex, ".$regex(blah,/blah/)" would actually result in mirc executing the /1 command, prefixed with the silencing dot. Changing mirc to not try to execute the return value would be inconsistent with the way it works in general. For example, having a variable as a command works fine (and I currently use it in a few cases), I would expect an identifier to work the same way.
Regarding the original suggestion, /haltdef is another alternative, if there is no halt-able event involved. I'm fine with /!.echo -q but I don't mind having a command that's 5 chars shorter (that's the only benefit I see with /noop; speed shouldn't be an issue since !.echo -q is already very fast).
