I saw that too. The announcement also included: "We also need to make sure all tests are scheduled for December." Having been guilty of failing to update the boilerplate in mass-mailings I've sent in the past I can sympathize with the sender.
I read in a testing center thread that someone was paid $40 to do this or a similar shop last year. I'd be interested in taking one at $50, but $30 doesn't motivate me as much. If I were to guess my theory would be that the normal rate for the shop is $30 and that the $50 reference was a bonus to clear shops in December. The $40 referenced in the earlier thread could have also been a bonus.