Thanks, Rob!

I assume you mean that the button would be disabled until they enter the required fields (or something to that effect).

The problem is that, for AT users, that's not announced. Potentially, you'd have to run checks on all the fields on every keystroke, because if you did it onBlur, then the button could be skipped before it gets enabled.

It opens up a lot of potential issues, both accessible and functional.

Thanks again!