Pedro, you (accidentally, no doubt) mixed up statements by two different writers, which can confuse others or give a false impression.

(I'd again suggest that you use plain text for such messages. Easier to show who's responding to whom, etc., and no incentive to top-post.)

DA>  My preference is for #3: we just bite the bullet and nudge
DA>  users helpfully toward using a separate file.

That was said by me.

+1

PL> It would work to make every one of these forms set a flag when they are loaded.

But that was said by Po Lu, not me.

Doesn't that go a bit too far? Other proposals don't depend on modifying custom-*