Aren't there already sites that show a fake permission request dialog? This won't stop them (and I don't see how you could without entirely removing the feature).
Mozilla has been promising to work on it and started a data collection program that I contributed to, but there are no news to share and the data doesn't seem to be publicly accessible. What a disappointment.
https://github.com/mozilla/popup-urls
Thank you for contributing!
Do you have information about the progress of the project? How about a new extension that makes you click to remove the pop-up? The data collected that way could almost directly go into a neural network.
Do you happen to know whether there are extensions to automatically answer GDPR pop-ups (indeed while blocking in page pop-ups these should probably receive special treatment)?