[lathiat]

This is actually very possible you'd be surprised. Find a keyless car system that also lets you start it such as in the Mitsubishi Evo X and test the range around doors and within the driver seat etc that it lets you start the car. Surprisingly accurate.

Key just outside the drivers door won't start and the boot won't open if it's basically where the tail light is etc. and that's 10 year old tech.

[dmoy]

What about the passenger seat though? My EE/physics is rusty, but inside vs outside of a giant metal cage might be easier than slightly to the right but still inside.