Useless and wrong
First it will most probably be completely useless (only MPs and ageing housewives are tech-illiterate enough for this to work. Unless the plods get physical access to the machine, but it's a completely different level of investigation then). Then it's dangerous (I give it 3 month before the stuff is modified and used by blackhats). Third, if the suspect is found innocent, it will be a very strong ground for suing the hell out of the authority responsible for compromising the computer.
A major FAIL waiting to happen. Which means, of course, that it's going to be implemented and widely used in no time, to investigate offenses such as littering, faked school applications and the like. You gotta love bonehead politicos.