So are you saying for sure that PVP is used, even for unencrypted sources like AVS-HD, when disc mode is used? In all commercial players?
It is clear that PVP causes this behaviour but it is not clear that PVP is the only way to get it or the underlying reason. Arcsoft say they use EVR and overlay combined, maybe that is part of PVP. But just using overlay seems to do much the same (although that has downsides in resizing quality etc.). It is not clear to me if others, like mpc-hc, could use EVR + overlay, or if the only way to do that is to fully implement PVP i.e. very unlikely to happen.