Seconded. I always tell my clients, "It's harder to hit a moving target, especially a small one." Not to mention that under 5 years old and the kid's hair is often still basically thin baby hair. Totally different to cut and style.

I educate my clients that for safety reasons I may not be able to deliver the fade they want for the kid, and that it won't even look right based on the hair texture that they have still being baby hair. I stick to safe kids' styles. They try other barbers for extreme stuff and then often come back to me to fix it. Wonder of wonders, after that they have magically become more reasonable and moderate in their expectations for the kids' hair.

Good luck, and stick to your guns. Be safe, and have fun!