Yeah, it may well be they are seeing if they can get away with it.
Tesla certainly has adjusted their policies many times.
I do wish they wouldn't try stuff like that, though. Just make nice, clean breaks for the future, but stop trying to meddle with past commitments like this or the performance counters or... (or repeating offers you once sold as going-away levers, e.g. free Supercharging).
It is perfectly fine to change policies for future new car sales (or Tesla CPO sales). Be clear about it and people can choose to buy or not to buy, very simple. Affecting products already sold, less OK IMO.