You don't need to read anything to know you don't tell your car to move by itself if you can't see it, with current Summon. With the new Advanced Summon, you would not need to see the vehicle because it would have move protections in place. But you still wouldn't Advanced Summon the car if you don't even know where it is (e.g. still on the lift or not)...unless you're a moron.

Its not an instruction, its a software limitation. If you aren't close enough to the car, summon doesn't work. I think its basically bluetooth range.

Enhanced summon is a different story, though that feature basically no one has yet.