Thanks!

> how is it reliably enforced?

At the chromium level, you have access to every single DOM element and coordinate space around it. So, when a click happens either user or agent, we have a neat way of enforcing required action (either allow it or nullify the click).

We are still at early version. And mostly targeting enterprise sites (like SAP) which don't change that often.

What use case did you have in mind?