I believe that by entering the PIN, you're agreeing to the contract. It seems like total "shit, double shit, and bullshit" to me, but it doesn't seem totally outside the boundaries of the law. Might be wrong, though, as IANAL.
Nope, the pin is purely a verification step for the points you're getting in return for the scam-signup.
The legal 'opt-in' step that the scammer claims gives them the right to bill you, is the 'enter your phone number for an SMS' step.
The opt-in probably won't be enough to satisfy the watchdog organisations that overlook this kind of stuff (ofcom in the UK for example) but it will be enough to broadside a legal complaint of simple fraud (ie, police involvement), and thus send the complaint to the watchdog authority...
The reason they do this is, if they can avoid the police shutting them down with a 'simple' investigation, then they get months upon months as someone like ofcom investigate, and during that time they can rack up the profit, then 'run' (declare bankrupcy and hide the profit) when the watchdog authority appears to be about ready to issue a fine.
(IANAL either, but have worked in the premium SMS industry, and seen this kind of 'ofcom-stalling' trick)
