It’s a bit of a strange feeling when a student cancels their lesson (or rather their parent cancels it) for a specific reason and then you find out later on, one way or another, that the reason they stated was completely made up… I used to feel annoyed about this, as I am an honest and open person. But then I realized that perhaps the child or their parent just needs the time for themselves, to do something else or just to be.
In my opinion, just being without the feeling of having to be anywhere or do anything is one of the greatest things that we can all do for our mental well-being. I think, therefore, that cancelling a lesson for this reason is completely fine; there is no need to come up with some excuse out of thin air.
The only thing that I expect from my students is at least 48 hours’ notice, as this will give me a chance to offer their timeslot to someone else. Whatever their reason for cancelling does not matter! What I find more awkward is when the student and parent know that I know that they had made up an excuse not to do the lesson. In my opinion, openness and trust above all!