I completed an online order on Sunday at
http://www.sjscycles.com and received a confirmation email. The email contained, amongst other things, my name, address, full switch card number, start and expiry dates, signature strip number, issue number, basically all the information someone needs to defraud my account.
Email is *not* a secure communication medium, the mail could have been intercepted and read *at any point* during its transmission. Alternatively, if I had have entered an incorrect email address, my full details could have landed up in someone else's email inbox.