Parents that have a day off bringing kids to day home

[mom-in-alberta]

My personal feelings on this issue: depend on the parents I am dealing with.
I understand that they have "paid" for the day. I also understand that it is waaaaay easier to get things done without munchkins tagging along. I had a dad drop off a while ago and outright tell me he was going home and going back to bed, since he was sick as a dog. I am fine with this, since usually it means a later drop-off or an earlier pick-up.
It bothers me if the kids are bothered by it. Last summer I had a mom who had 3 kids in my care, and took a day off. Fair enough. She called that morning and said she'd probably be about a half hour later than usual dropping off. Fair enough. She showed up within 5-10 min of the usual time, which is fine, but why would you call and tell me otherwise?? (Also, I was gleeful that I might enjoy my morning cup of coffee in peace and silence, lol) She then told her kids she had a spa appointment, kissed them good bye and did not come back for 10 hours. I mean, she still picked them up at 5:29pm!! (As late as she could, basically)
These kids had just gone through their parents divorce, moved provinces and schools and were SCREAMING (sometimes quite literally) for attention from their parents. All of them were of the age to know that mom was not working that day, and still chose not to be with them. Not even for an extra hour or two.
That bothers me.