I hope you’ll allow me to reopen this discussion… there may be a way to resolve it after all.
I was wondering why I could sympathize/agree with both of your arguments, and I think the difference is that it really matters what kind of work we’re talking about.
KB is talking about mission-critical work, whereas you are (I assume) talking about a kind of modern knowledge work. Imagine going to the dentist, making an appointment and having it be a maybe until the evening before. Nobody would like that, or ever come back to the dentist again. Their work needs to be done by a particular person at a particular time and place, so it matters that promises are kept and claims on time are honored.
Now imagine meeting up to write a PR strategy with some colleagues. The ground truth with a lot of knowledge work these days is that each individual contribution isn’t always critical to the outcome. Almost all of the meetings I am in do not need to happen that day or that specific place. They should probably happen that week, but if they’re postponed by a day or two the consequences are usually zero or manageable.
Now that doesn’t mean each attendee’s contribution to that hypothetical PR strategy meeting is worthless; it usually just means the conclusions reached have a blind spot, or are less good than they otherwise would be. Usually, that results in one or two questions being raised during the meeting that person X who’s not there should know, so someone jots it down to ask them later, or a decision is postponed until that person has clarified a thing. Again: there are consequences, but they are low.
What I’m trying to say is that any specific person’ s absence in knowledge work is largely inconsequential, which means that an uncertainty in anyone’s presence is much, much less of a problem for everyone involved.
Then there’s also a difference in what happens when someone reappears. “I took PTO but I changed my mind so today I can work” sucks balls in healthcare, because there aren’t specific demands on specific persons just ready to go.
On the other hand, I had this Monday blocked entirely because of a conference that I ended up not attending. Because a lot of knowledge work is divided in a small, important, focused set of work that Needs Done Now and a much larger, nearly endless list of less important / less urgent work that Needs Done, Well, Whenever, But Not Never, I could just pick stuff from those two lists and work on that instead. For the first list it means you get to improve the expectations you set earlier. “Hey, I thought I’d send you this on Monday, but I found some time to do it today so here you go!” For the second list it usually only matters that I do it, but not when or where.
In other words, because the consequences of pushing knowledge work around are so much lower than that of anything KB’s used to (healthcare, engineering, …), and because it is so much less time/person/resource specific work, it really does make a difference in how much less of an annoyance it is to have someone who retracts their announced PTO.