The Cam slot is hidden behind a panel held with two screws (on the ones Ive seen)
So far there is no firmware in the receivers (and some people report that it may never be a possibility on the original four manufacturers - simply a minimum peacemeal requirement to conform with European legislation)
Yes, as CH says, can't do anything with the cam slot and the Videoguard unit is embedded so can't do anything with that either. Perhaps it should have been a requirement that the CAM slot was proved to be functional.
Just me being idealistic CH, if something is required by law, then the law also should reqire that it be functional. The law requires motor insurance to legally drive a car on the UK roads, but it also requires that it be at a certain functional level. Any sensible receiver specification legislation would apply a similar rider to it's stipulations, but then who ever accused the EU of being sensible