AFAIK 433MHz can be used for any short-range application, similar to 27/49MHz for R/C cars. There are plenty off-the-shelf 433MHz transceivers for hobbyists, a

AFAIK 433MHz can be used for any short-range application, similar to 27/49MHz for R/C cars. There are plenty off-the-shelf 433MHz transceivers for hobbyists, and I think car remote-unlockers use that band as well. And this doesn't appear to have a particularly powerful transmitter, so you'd have to bring the transmitter relatively close to the receiver (like <100ft, usually) in order to download...whatever. If they're able to put this thing on your car in the first place, I guess it's not infeasible for them to drive by to download updates.