Entrapment. My top fear, right after heights and too thick (or thin, for that matter) a glaze on my creme brulee. No matter what I do to ensure my car is properly lifted and secured, there's a nagging fear in my head my repair work will end tragically, where my last sight is the under-body of a Ford Freestyle before my demise; at least I will have the happiest widow in the tri-county area.
Lifting the rear of the Freestyle requires more forethought, because there's not a good lift point aft of the front door where I can fit a jack and then a jack stand to bear the weight while I'm working. To lift the car, I jacked the front enough to lift the rear tire off of the ground and then placed a jack stand at the rear of the car on the unibody rails where one would put a scissor jack whilst doing a road-side tire swap-out.
Once the wheel was off, the sensor was nicely exposed and I had (just!) enough clearance to do what I needed to be done.