> Whereas in the UK, cancelling an annual travelcard has at most a £10 administration fee and you get a refund based on when you cancelled

So, how do they motivate people to buy the annual subscription when there is no monetary advantage for binding yourself yearly instead of monthly.

In Berlin, if you get an annual subscription instead of a monthly one, you will get two months for free.

And if you cancel early instead of waiting for the whole year, you pay the difference between the monthly and yearly subscription for the months already used.

I don't see anything scummy or illegal here.