To give everyone an update, I tried activating my passes today, and it seems the loophole is now closed. The annual pass system is linked to the DVC system after an update sometime in the last day or two, according to the cast member.
I was at Disney Springs and neither the ticket center or guest services was able to activate my pass, getting an “ineligible DVC number” error. So they were unable to activate my Sorceror’s pass purchased with a white card. Fortunately, the very helpful guest services representative upgraded me to the incredi-pass at no extra cost since they were unable to activate my card.