With the systems in use today, I completely agree: paper tickets give away less information, and even less so on the 'gateless' metros that sibling commenter To

With the systems in use today, I completely agree: paper tickets give away less information, and even less so on the 'gateless' metros that sibling commenter Too mentioned, such as in Berlin. I'd say that the systems that are most invasive are VISA/Mastercard-based ones such as the London Underground; TfL have immediate access to your bank details from the moment you pass the turnstile. I hope that digital options which are as private as paper tickets will be implemented, because I don't want 'digital' to mean 'surveillance' by default!