3rd choice
Opt-in vs opt-out -- they could just have no default but disable the Next button until the user has chosen either one. That'd probably get a bit more participation than a basic opt-in, while less than a simple opt-out.
Opt-in vs opt-out -- they could just have no default but disable the Next button until the user has chosen either one. That'd probably get a bit more participation than a basic opt-in, while less than a simple opt-out.