I was under the impression that the tug drivers and wing walkers are paid by the airline, not the airport
I have no idea about Schiphol, but the European airport which handles my client's airplanes has airport employees, not airline staff, ground handle the planes. I know this, because we've had two "incidents". I recently discussed with the airport manager allowing us to move our own planes, as long as no one else's plane is around, and that seems likely, though a stretch of their rules. It will be less costly for them, after the rather expensive repairs which have been incurred by the airport. When we move the airplanes, we always have wingwalkers, and a following person. A few times, the airport staff have moved our planes without our assistance, and twice it did not work out so well.