I recall only too well the (justified) painfull lead up and eventual introduction of CVR's into the industry.
Many in Management did not appreciate Pilots real concerns and many Pilots displayed a degree of undue paranoia.
The intro eventually came to pass and 'yes' it has been a plus for aviation safety.
Now In 45 years flying, with various organisations, I cannot recall a single incident where a colleague was 'gunned' because of the CVR
It probably did happen but I never experienced it. There are bad guys on all sides so negatives are inevitable.
I'm in favour of CCTV but like St Agustine, not just yet. The appaling change in western society 'normalisation' of dishonest behaviour and the carry on of those in modern day politics give me real grounds for concern. As long as it's profit before principal I'm a no vote.