The only thing that I could think of is if the protector that is around embellishing machine needles could be adapted to the machine? However, it may defeat the purpose as it could be harder to see where to sew.
I have little kids sewing with me a lot and my philosophy is to teach them safety with the right gear and procedure as I think people have accidents when they are struggling with blunt scissors etc. However, I am not trying to dictate what you should do - safety has to be the prime concern. I have had 4 - 7 year old boys and girls manage OK. However, I must say I have an 'eagle eye' on them ( reminding safety rules) and never leave the room if they are in it.