Personally I wouldn't call either of those "closed off gears", they ( the larger gear ) is facing inwards, but plenty of opportunity to get small fingers "nipped" in between them and the "pinion" gear on the shaft. Or between the larger gear and the shaft nearer the chest plate.
There are some similar models where they are totally "closed off"..I can't- find a picture right now, and have to go out soon, but IIWY, I'd keep looking.If there is a way to hurt themselves, a child will find it. Someones else's child's parents may not be as understanding as you'd think. Public liability insurance ( you do have it ? ) and even if you do, being "bad mouthed" by "injured" child's parents to all and sundry even if you are insured could make your life hell.
Yes..over reacting, but I've seen it happen ( not to me thankfully ) some parents will always blame someone else, loudly, and possibly all over "social media"..and their friends and neighbours will side with them, and repeat the bad mouthing.
I'd have let my lad use them when he was small. In fact I had some the same and he did.And he got his finger nipped ( in the way that I said ) squealed, cried a bit, bruised and a drop of claret.Me severely chuntered at by his mum. Someone else's kid, with a facebook account or a large group of friends and an urge to make waves..could have been nasty.I had good public liability at the time..I used to make the floats for our local kids carnival, and some costumes , meant I shut down work for 3 weeks and just built ( welding drilling sawing, painting etc ..big floats , pulled by tractors ), cost me money to shut down work for 3 weeks, plus I paid all materials.
It was good advertising for me. But I still lost financially on it all.
But I did not allow kids or parents into the atelier at all during that 3 weeks.They saw the results when I pulled them outside the atelier onto my car park.
Not before.
I didn't need the potential agro of a kid ( or parent getting their finger nipped in a pair of pliers etc and making it my fault.
*I rarely allowed the public in anyway, if they "had" to come in, we had a waiting room decked out with comfy leather chairs and plants and posters and photo books of what we'd done before..Only me , SWMBO and our lad in the actual atelier ( 350sq meters ) ..ever..