It's absolutely not a reasonable thing to define and target. The bottom line is the feature is a FEATURE and will continue to exist, so trying to police how far websites take it is ultimately a non-starter.

Browser vendors could hypothetically start adding specific types of exceptions to make certain types of the 'hidden box' trick not work, but that would ultimately mean those website developers simply switch to whatever method works. The problem isn't solved, it's just re-coded.

TLDR: There is NO SOLUTION, because there is NO PROBLEM. The feature works as intended, as written in the spec.