Oh, I wonder if this is actually the (at least short-term) motivation for Google's much-criticized WEI [1] efforts?

MASQUE lacking a feedback channel for websites to report spam/abuse was explicitly given as a motivation there, as far as I remember.

I'm still skeptical of WEI as a whole until we know more, though.

[1] https://en.wikipedia.org/wiki/Web_Environment_Integrity