In London you can now report the driver if they're on the road with a "broken" card machine, as that makes the car considered "unfit".

A lot of drivers still use unapproved card devices, though (TFL points out handheld terminals are explicitly not approved, yet I regularly have taxi drivers insist their fixed terminal isn't working, and to use a handheld one), which I'm taking means there's assorted tax fraud going on.