Kind of funny to think car thieves also have range anxiety. :)
The only time I've had a car stolen was years ago from a valet at a high end restaurant in Atlanta. They drove off with my BMW, two Mercedes and a Porsche.
There is a thread on another forum that addresses this issue. Porsche is reading the actual power going to the battery after parasitic loss from other systems like heating/cooling of the battery and cabin air etc. Tesla likes to show the higher/more optimistic power coming from the charger.