Uh, I believe you would have a red "REL" line from the time you called until said trip. So, technically, you would be released and no longer on reserve.

Technicalities aside, I do agree with you that under most circumstance we should be able to show at show time and do our jobs well. If that's the first time someone sees the FPR/Wx/Notams, that okay. I wouldn't expect anyone to show up a minute sooner - but I do expect them to show up prepared. Whatever that means for that particular flight.