Once that happens, it wouldn't be just tesla's that will be auto parking densely. Any other car is equally susceptible to cause fire as all cars have batteries

Once that happens, it wouldn't be just tesla's that will be auto parking densely. Any other car is equally susceptible to cause fire as all cars have batteries and most have inflammable fuel. Its not yet here, but auto parking densely probably meant cars can be tightly packed as you don't have to leave enough space for you to open doors. As the car is self driving, it can go to the garage and park next to some other car. Its doable now, if those garages have some sort of beacon to notify unoccupied space and if all cars have beacons to notify/detect its edges. Its not hard to implement at all.