There's a general move away from having boxes automatically ticked for online services. It has come about because the Consumer Contracts Regulations (which came into effect 6 months ago) now mean that online traders can't charge for pre-ticked items. (e.g. airlines are banned from offering pre-ticked insurance and then charging for it).
While free services, such as AB's 'subscribe' option, aren't covered by the new legislation, many websites are now removing pre-entered ticks from option boxes anyway.