Maybe I'm misunderstanding but are you suggesting some of the only people actually allowed to drive at 80 in a 60, who have training, experience and constant supervision, should not do when they have been presented with an opportunity to identify a persistent offender?
OP may well get away with her offence but police can and do prosecute speeding based on video evidence collected by cars even technically on another job. Forces now welcome the upload of dashcam footage showing dangerous driving and again prosecute if it's good enough to clearly identify registration numbers.
There's a good summary here.
"A total of 32,370 pieces of footage were received by 24 police forces that accept video evidence of driving offences from members of the public, double the number recorded in 2018 (15,159).
Data from the RAC’s freedom of information request also shows that a quarter of these (25 per cent – 8148) went on to result in prosecutions.
Police forces, according to the RAC’s study, are making it increasingly easy for drivers and other road users to submit camera footage of unsuspecting alleged rule-breakers, with all of Britain’s 44 forces now accepting dash cam video, and the vast majority online via their websites."
"...revealed that more than half of the videos uploaded to its safety portal have resulted in further police action. Favoured by police for saving an average of eight hours per case, Nextbase says its platform had saved these forces at least 170,000 hours.
The footage submitted to police related to the following offences: dangerous driving, careless driving/driving without due care and attention, driving too close to cyclists, contravening red traffic lights, contravening double white lines, contravening ‘no entry’ signs, illegal use of a handheld mobile phone and evidence of vehicles apparently without MOTs.
RAC road safety spokesman Simon Williams said: “Even before the decline in the number of roads police enforcing traffic offences, law-abiding drivers were often frustrated that there was never an officer there to deal with infringements they witnessed.”
“As so many drivers and cyclists are now using dash cams and helmet cameras every road user needs to be very conscious that any of their actions that aren’t in accordance with the law could end up with the police. Some will inevitably find this out the hard way while others will hopefully become increasingly mindful of it.”
Times are changing for smug speeders, close passers and other shitty drivers with GoPro helping rebalance things for vulnerable road users. There are people on YouTube making a good living out of getting people prosecuted, with only a helmet camera.