Yet they (the Germans I've known) don't seem to give a second thought to handing out their bank account numbers to businesses for electronic payment purposes.

Yet they (the Germans I've known) don't seem to give a second thought to handing out their bank account numbers to businesses for electronic payment purposes. Discount card use seemed to be widespread as well despite all the tracking that inevitably comes with it. I never once got through the check-out stampede at Rewe without being asked if I had a card. I met some wantrepreneurs in Berlin who were hatching discount/reward card schemes of their own, not something that would attract much investor attention here in the States, unless of course it was "the Uber of discount cards". No, stop, that's not an Idea.