[refurb]

What do you propose they ask for instead?

Plenty of "open source projects" are nothing more than some informal group working together. It's not like they are registered with the government.

[olddustytrail]

A TXT record added to the domain seems like an obvious solution, especially for a tech company.

[refurb]

That's a reasonably "secure" identifier, but I suppose not everyone does it. So Twitter is a bit stuck trying to come up with "something", even if it's easily faked.