Yes, I turned my 11 year old loose with his first bow at Marshall, MI. I rushed through a dozen "Tony Stewart" colored arrows and didn't trim the feathers. He came back with bruised, bloody knuckles. He was shooting for about an hour. I told him to stop and let me trim his feathers for him. He refused. He didn't want it to take any time away from his shooting so, off he went and shot another couple of hundred arrows at the practice target. Finally, when his index finger looked like hamburger meat, he let me trim the feathers. He went back at it though. He loves his bow.
Had a hickory backed bow that I was recently making. After removing wood in the tillering stage, I exercised the bow, drawing, releasing, drawing, releasing (you know, how the books say to do). I decided it was time to shorten the string and bring it to brace height. I use the "push/pull" string-up method. (If I'm not strong enough to slide the string up into the groove, I know that I have to reduce some more wood because its probably an 80-pounder). I struggled a bit, likely it was around 70 pounds. Immediately after a loud CRACK, pieces flew and the rest of the bow slapped the tender underneath of my bicep causing a silver dollar bruise. Kinda hurt, too. My son who was there said, "Was it supposed to do that?"