Some trackers are magnetic and can be quickly placed under a car.
You might want to use a mirror to check the undercarriage without lifting the vehicle.
Although it's less common due to the risk of heat damage, some might be placed.
Webchances are the gps unit was put by a previous dealership before carvana, and it's just been left over in the car and not seen by anyone.
Webi know this is old, but they absolutely do install a gps tracker with remote kill.
Just google it and you even get the carvana installer instructions.