The thing about good safeguarding is that in many ways it's contrary to human nature. Human nature is that you are part of a group and you trust members of that group and don't examine their behaviour too closely / give them the benefit of the doubt and assume good motives / don't examine the impact of their behaviour. Safeguarding is that everyone is viewed with suspicion with the goal to keep children safe and that the impact on children is put first regardless of whether the people who are impacting them have good intent or not (you could put the insanity over pronouns in this category in many cases). You don't take things on trust.
DBS checks should be part of a far wider safeguarding culture but people think DBS is enough these days - it's become a bit of a tick box exercise. Still important but not sufficient. Paedophiles will always have a period before they're caught, after all.
In the last training I did specific cases were mentioned where safeguarding failures had been found (one of which was abuse in a nursery setting). In every single case the person who blew the whistle had nothing to lose. Whistleblowers are often treated very badly - see Sonia Appleby at the Tavistock and the treatment she received for trying to do safeguarding properly and the other Tavistock whistleblowers too.
In the nursery case it was a girl who was doing her A-levels doing work experience who reported, supported by her parents. She was also financially supported by her parents and on track for university. Nevertheless the training still emphasised how difficult it was for her to report as she knew that colleagues she liked would be unhappy at her reporting and that possibly lose their jobs if the nursery was shut down. But really, she had nothing to lose, it wasn't going to affect her life. There were quite a few other people working at that nursery who didn't report and probably knew what was going on or saw red flags and did nothing because they knew the consequences could be bad for them, most of them probably needed their jobs to survive.
So it's really important that people on the 'outside' of groups can raise safeguarding concerns because to some extent it's difficult for people within groups to do so, and for there to be safeguarding loopholes. The other thread about the theatre director also illustrates this. How many red flags did there need to be there FFS?
In schools there are processes put in place which make all of this easier and more robust and less personal, although human nature is still human nature so people will still let some things slide for people they like and of course there are grey areas. Of course, sometimes safeguarding concerns can be wrong, but the correct response to a safeguarding concern is 'oh my goodness, let's investigate and discuss this I really hope my actions haven't made children less safe' not 'you're being a big meanie and weaponising safeguarding'.
Everyone gets things wrong at times, but if your response is 'nothing to see here' rather than 'oh god, I hope I didn't make a mistake, let's examine what happened' that's a red flag.
Really if safeguarding is being done correctly, then there will be investigations where no action is taken and where the concerns are found to be baseless.
There's also sometimes a tension between safeguarding one child and safeguarding an entire class / school which can be difficult to balance.