Watch out when doing business with non-UK data controllers
This really irks me because if Amazon.co.uk - a UK facing website, were a UK data controller, then we could just do away with nonsense like this. Under UK law we can opt out of all marketing under section 11 of the DPA. There's nothing that a UK data controller can do to negate this statutory right. In which case, Amazon wouldn't be able to make offers like this because UK organisations cannot make the receipt of direct marketing a condition of doing business with them.