> Sound like a strange place to have a captcha indeed. What information is needed in the form to submit it? Does it validate stuff that an attacker might want to scrape? I guess they added it for a reason.

Ive seen captchas on payment forms to prevent credit card checking. You can take a dump of CC details and try them all out on a site and get back the valid ones. I'd assume they charge $1 to the CC to test it before allowing you to continue and then you could cancel your order before they charge the full amount. However, assuming you have to be logged in to pay your bill that seems less reasonable.