I think the US nonimmigrant visa application must usually be done online (some exceptions exist) using an interactive series of web forms. So your solution works if and only if they don't apply validation rules to that input field and throw an error.
I guess they may have some procedure to handle the case where technical limitations of the form prevent an accurate answer, but even if yes that's still a huge obstacle many applicants won't overcome.
(Yes, applicants with the technical savvy to catch-all domains are more likely to be able and willing to overcome that type of barrier. Other categories of people will have a harder time, like who are sure they've forgotten some email addresses but don't remember enough details to reconstruct that info. They'll have to say exactly that, if they can even find a place to provide that answer, and possibly get refused as a result.)
I guess they may have some procedure to handle the case where technical limitations of the form prevent an accurate answer, but even if yes that's still a huge obstacle many applicants won't overcome.
(Yes, applicants with the technical savvy to catch-all domains are more likely to be able and willing to overcome that type of barrier. Other categories of people will have a harder time, like who are sure they've forgotten some email addresses but don't remember enough details to reconstruct that info. They'll have to say exactly that, if they can even find a place to provide that answer, and possibly get refused as a result.)