Over the years I have seen the need for cables on rear brakes discussed many many times when it comes to rally cars. I don't know how the electric handbrake works. but other than that they are needed for an MoT test. It has been widely quoted that quite a few years ago a well know motor manufacturer was told by Essex police that should there be another occasion when one of their rally cars was stopped and it didn't have a working mechanical handbrake the company would be prosecuted. The risk of bad publicity made sure it never happened again.
I have also seen cars being checked at scrutineering for handbrake cables. As scrutineers seem to have their favourite things to check and they don't all check everything, just because it hasn't happened yet doesn't mean it won't. E.G. In South Wales it is common for scrutineers to test the cut off switch works with the engine running. Buthtis didn't happen at the Showground Stages last Saturday.
