Thanks Jose, this tool only does work for the administrative user but this sounds like a good enhancement request to me.
However, it is it still possible to see users connected a few other ways. The simplest method is to do a selection from the Geodatabase process_information table. This should have the same information you were seeing from sdemon -o info -I users. This table by default is accessible through the public role, so any user will be able to select from it.
I know this goes without saying, but only selections should be run against this table, no edits.