No idea!
BMW uses two different types of tire pressure monitoring depending on the market: an actual sensor in each wheel, or, it relies on the anti-lock brake sensor to distinguish differences in tire rotation rates (a lower pressure will mean it will rotate faster than the others unless they all are low!). The service manager indicated to me that the TMPS sensors on the i3 actually broadcast when they hit top dead center periodically. The only thing I can think of is if all of the sensors were installed at top dead center, they might start broadcasting at their intermittent rate, and kill their batteries if it was left there for awhile. But, they also have a motion sensor in them so that they only start broadcasting when the car is actually moving, so that doesn't hold up.
If you get a good explanation, please pass it on!
