I'm relying to you now because you've specifically asked me a question even though in the same post you asked people to stop quoting you. Odd but hey ho.
To answer your question at present I do not work in a job that needs weekend or over holidays cover (Easter, Xmas etc) I made the decision to change my career when I decided I would like (hoped to have) chn in the future.
Before this decision I worked in 3 different jobs where weekend and holiday working was part of the contract. So I guess, this is rough figures as quite a few years ago, around 100 ish people as colleagues over the 3 jobs.
Generally most people are fine and respectful, but I did come across, I think 5 if I remember correctly, that would not take no for an answer when asked to swap for Xmas and Easter at some points. I was a lot younger late teens and early 20s, I was told that I didn't need Xmas off as I was only going to see my parents and it didn't matter if we celebrated on the day or not. When I declined their request stating that I had worked the holidays previous years so would be taking that year off, as the rota stated they were not so nice, making things uncomfortable at work by talking about me behind my back saying I was selfish etc.
So to answer your question I have met enough to know that people like op colleagues do exist sadly. They are not the majority but they do exist and this does happen. I would say the frequency depends on the pool of colleagues you work with.
Your analogies of happens as often as someone murders their colleague is quite frankly ridiculous, can you not see the difference between murdering someone (quite the extreme occurance), to someone using their kids as a reason that should be able to cherry pick shifts?
This is obviously something you feel strangely passionate about, but surely you can at least imagine that it could happen more often that you have seen? And the fact that numerous other pp have confirmed they have themselves been in this position, you still seem to think everyone is lying. So again I don't think the op answering you directly will have any baring on your thoughts. You refuse to take others experiences into account and only base things on your experience. 🤷♀️