For what it's worth, the AA Million Miler benefits are fairly well-documented - well enough that AA sent me materials on company letterhead about it along with luggage tags that say "Million Miler" on them. When people say it's "undocumented", perhaps they mean it isn't listed on the web page that lists the usual Gold/Plat/Explat qualifying rules, but you can rest assured that if you hit 1MM today, AA will send you your Lifetime Gold letter without you having to know a secret handshake something like that.