I wonder how this is enforced? Is there some kind of mandatory registration with Ford that is required for the car to work? Or are they threatening to sue if they find out you sold it?
Any car I have owned, reselling it has nothing to do with the dealer. This is one reason I would never a vehicle that came with any kind of software subscription from the dealer / manufacturer. It's just another tool they can use to extract money from you and deny your ownership rights.
In this case, it's not clear what the enforcement mechanism is though, it may not be software related.