If asked directly, I will tell a scheduler the reason even if it is a personal one. They are human and understand the every day issues we all have in our lives. What bothers me about the response is how it flies in the face of everything we strive for every day, professionalism. We want companies to recognize we are professionals and as such we should treat them with respect. Anything from, "I'm sorry one of my kids got sick," to "I've been working on a route and the shop will fit better on this day," are appropriate.
I have this question for the OP, how would you feel if you scheduled an appointment with an electrician and after you arranged your schedule he/she asked to change with the reason, "I have kids. Things come up!"
Equal rights for others does not mean fewer rights for you. It's not pie.
"I prefer someone who burns the flag and then wraps themselves up in the Constitution over someone who burns the Constitution and then wraps themselves up in the flag." -Molly Ivins
Never try to teach a pig to sing. It's a waste of your time and it really annoys the pig.