At this point, I have done very few structured projects, I usually just let the kids have at it with the bin of wood scraps. Kids don't need to be told what to build with the scraps, their imaginations kick into high gear and they figure it out naturally.
I call this the "empty box effect." An empty box is an open ended toy and a child's imagination starts exploring all of the possibilities of what the box can become. The same thing happens with the wood scraps.
During the kids' build sessions, there is plenty of opportunity to teach them about safety, how to use the tools, and problem solving skills.
I think that both structured and unstructured projects have their own advantages and lessons to offer, so I do not necessarily value one over the other. But I will admit that structured projects require more prep time because you have to make parts in advance.
When working in the shop, the kids are exposed to a limited set of dangers, but that is an inherent risk of having them in the shop. Overall, the exposure is controlled and gauged according to the abilities of each child.
The fear of allowing kids into the shop will never give them the opportunity to learn self-control and respect for the tools and a somewhat hazardous environment. Personally, I don't see that it is any less hazardous letting kids ride a bike, a skateboard, or jump on a trampoline. I will not allow an unreasonable fear to keep my grandkids from such a valuable learning experience as they have in my shop.
