I do not see how legally they could do it without paying us, and crew logging the time. Any time the aircraft moves under its own power, there must be a Commander in charge, and it is considered "block time".
I still think it's not going to solve their problems, especially when FDP is close to max limits already, but hey - taxi away and pay, pay, pay.... They will soon learn that it costs a lot more for an aircraft crews' time than just sorting out the problem.