As for those worrying about the reliability of a wireless system, and the possibility of catrastrophic faillure, there's a pretty simple answer.

Design the sytem so that a failure results in the application of the brakes, such as the spring brake in the trailer of a tractor trailer.

If the trailer on a tractor trailer loses air pressure, due to a damaged or improperly hooked up air hose so that the trailer brakes don't operate properly, the spring brake automatically engages.

It shouldn't be much trick to design this system so any loss of signal or corrupt signal results in the brakes automatically applying. This would be an improvement over the current brake systems where loss of a cable equals no brake.