Well, it arrived yesterday morning. The pad came. Rather than DDRMAX2, they included... wait for it... Dance Dance Revolution Disney Mix. The packing list is correct, someone just grabbed the wrong disc.
I find this rather amusing. I have *no* interest in using Supercalifragilisticexpialidocious, It's a Small World, Donald Duck's Birthday Song, the Mickey Mouse March, and so forth for my daily dose of accelerated heart rate. I expect that Red Octane will send out the right disc on Monday. I'm also expecting that they'll want DDR Disney back: it appears to be quite rare. It usually goes for $70-100 on ebay. Well, fine, I'll happily send it to them... if they pay for shipping.
Meanwhile, I wish it were possible to get older mixes (say, 4th) for the PS2.