I have used ZED to list for 2 flights with other carriers, they sent me an e mail confirming I was listed. The system does work.
On the ZED listing site there are not so many airlines that one can list for at the moment though or perhaps I do not know how to use zed.com properly.
I did as I was instructed on one occasion and telephoned to list myself with one airline to be told I could only list when I checked in which I did. My experience is I have always been listed at check-in and have been accepted for the flights.
I only use staff travel for holidays, I have not been a commuter.