My presence stuff is a little bit of a mess, due to my wife not wanting anything done to her phone. She's OK w/car presence that doesn't require anything on her phone, so do I have presence sensors in the cars for the primary purpose of opening the garage door when we come home. No close automation due to safety concerns.
I've had zero false positives, as my rule requires both presence change to present & presence sensor on DC power, which only occurs when the car is on/running when I arrive home. When the car is off the sensor runs on a built-in battery. Very reliable (zero false positives), and one of my very, very few wife-delighting automations.
So I have "who" is present info for myself via Owntracks, "car presence" for both cars via @iharyadi's excellent presence sensor, and only a very vague idea as to where the heck my wife is. 
