If you tell your kid you're going to take him to a movie with every intent to do so, then get called in to work or get hit by a bus on your way home and are unable to, did you "lie" to him?
I am pretty sure the sheriff didnt get hit by a bus or called to work lets be realistic, but to answer your question yes my kid would feel like I lied to him. He may understand the circumstances but he is still going to feel I was dishonest... well unless a bus hit me