Well, no, the FAQ states they aren't allowed to require or insist on documentation. It states absolutely nothing about asking for documentation. It's a semantic point, to be sure, since we're clearly in agreement over the gross details... but the FAQ doesn't prohibit asking for docs, it just prohibits requiring them.

It's kind of a moot point anyway, because as has been mentioned a few times previously, the ADA does not apply to airlines; the DOT/AACA does. The details are similar in that the airline cannot actually require documentation, though they may still ask.