It would be interesting to know how they calculate that figure ! Does the combination of ID cards and heavy fines make fare-dodging a much more difficult and expensive course of action than in the UK ? Presumably there are consequences if someone does not have, or refuses to produce, their ID card on demand from an authorised person.
Good question - and I have no idea in terms of how the figure is calculated (likewise I have no idea how the RDG calculated their figure).
Being German, the procedure is incredibly organised and quite bureaucratic - see the official explanation
here. (And, yes, it is in English on their website!) Of course you do not just need a ticket, it needs to be validated as well. Sometimes they'll let foreigners off in terms of the validation, particularly if you are coming from the airport (as I once was), but I've heard of other inspectors being stricter.
I've just been speaking to my German friend and mentioned this. Technically, you must have ID, but it is
not compulsory to carry it with you. But you must provide it to authorities on request. German police have quite wide powers to ask for ID, and to detain someone until they produce valid ID, though my friend says this is rare, as most carry it habitually, as we might a drivers' licence, unless they're just popping to a local shop or the gym. Carrying it just avoids hassle if you are asked for it. I visit Berlin at least a couple of times a year, and I have only been asked for it a couple of times in 10 years.
The fine (see
here - in English again!) for not possessing / presenting ID when required (section 1) is up to 5,000 Euro (section 32). I suspect the average fine is a lot less, but I don't know. That's a decent deterrent, though.