I'm wondering if rubber bushings could be put between the cage and helmet (at each of the mounting screws) on a hockey-style mask to povide a little extra give on impacts to the cage. I might look into this on my DD's mask.
I would worry about the screws loosening if they were not secured snugly, which might be difficult with rubber bushings installed. Maybe if you Loc-Tited the screws it would prevent any issues.