I received the offer on my 16 year old Reddit account, but not on another account I have that's more like 12. Not sure if they went by account age or activity or what.
I can only imagine that they're offering it to me because my account is like 15 years old.. Either that, or I have about 200k post karma and 100k comment karma. (Not big numbers compared to karma whores, but still more than your average user).