This smells like bullshit. No offense to the O.P..
My guess is the same shit that happened to me. They want/need their details on the payment page (or whatever it was) for MasterCard or one of the credit cards. Citing that it was some sort of banking requirement. You simply had to cut and paste some code, and throw it on the join page if memory serves.
Annoyance? Sure. I do not like threats of losing my account for some minor b.s.. But it's no different than a merchant account where they have their own list of demands of things you MUST have on your website, or you are not going to be in compliance. Rules of the game.
