There, but for the grace of God, goes any pilot - professional or otherwise. Anyone with a licence can be on the receiving end of such a prosecution.
Rather than running a kangaroo court to decide the blame and the punishment, why not use the grey cells to discuss the problems inherent in Rule 5?
Your cockpit instrumentation can be set to give you a reasonable vertical reference to the nearest (maybe) 250ft. But how do you measure 500ft FROM anything? Similarly, how do you measure 600m FROM the nearest highest object in the 1000ft rule?
What if the subject is moving? Have you seen what 500ft looks like on a quarter-mill?
Your helicopter generally wasn't designed with Rule 5 in mind. It will tell you speed, alt or height vertically, rate of ascent/descent, direction of travel etc. But it would need a certified and very special device to make any readings of distance FROM a person, vehicle, vessel or structure.
Similarly, how does the reporting witness measure with any accuracy those same distances?
It is high time the UK adopted the US rules in this respect. There they simply prosecute for endangerment - which, after all, is what Rule 5 should be about. Instead we live with a scenario that everyone, including the FOI of the CAA, hates the drafting of Rule 5, but does nothing about it.