Speaking only for me and mine, but Cygna's not. Cygna was aware of the effect that Aegis has on Parma. The player, on the other hand, is trying to wrap his head around this new house-rule. If, in your saga, Parma Magica is a de facto Rego Vim effect that has to penetrate an Aegis's level to stay up, I'm fine with that, now that I know about it. It makes a character have to choose between, oh, surviving a Ball of Abysmal Flame and being able to interact normally with magi in other covenants, though.
We've at least mentioned that in-character. All anybody knows is that it's some kind of Mentem, but that's all any of us know.
See, now, this is new. I went back and reread pages 5 through 7 of the Policy and Protocol thread, then reread them again, and reread the post where we took the oath a couple of times to be sure I didn't miss it the first half-dozen times or so. And I am still not seeing anything indicating, either in- or out-of-character, that either the players or characters knew any of this. Maybe I'm missing it. If so, please tell me where it was so I can slam my head against my cricket bat a few times, because I hate feeling like I missed something obvious.