The question stems from an experience I had, where despite the NOTAM stating otherwise, the RA2 was activated at short notice.
I checked the ATIS prior to entering (as I always do) and realised the RA2 was now active. I requested and received a clearance, but then got a polite reminder that flight planning through the airspace is not permitted.
I didn't have the effort to argue over the radio that they were deactive when my plan went into NAIPs 2 hours earlier...
OK, supplementary information: from my time of initial departure until about 20 minutes prior to arriving at the RA2 boundary, I was in class charlie. Centre hadn't offered me any updates or info on the activity of the upcoming RA2...