Just to give a clear understanding about the plans, it's origin and it's contributors.
Popular Mechanics is where the plan came from, Popular mechanics plans are from mechanical engineers and all meet the safety standards of that time frame. No one rather it be private or public leaves their children unsupervised, unless for the obvious reasons such as abusive uncaring parents. I think we can all agree on this. Rather anyone takes the plans and use them is totally up to the forum member. If, you go to youtube will also discover how families are making such homemade rides and spend more time with their children because of it. There is always PROS and CONS to anything you do, even holiday lighting. You can be libel for causing a distraction to drivers on roads within sight of your display (given a case of an auto accident or traffic infraction). Even with the best of care from anyone doing holiday light shows may be unsafe unknowingly. So, also consider the same thing you are citing to me falls under the same as for holiday decorating period. Lightshow, static props, ect... electrical inspector, fire marshal, insurance are all under your liability as well. Can you say that you have enough dedicated circuits for your decor? can you provide all electrical permits that would be required under the same conditions proposed in your response? Did you hire an electrician to put up your props? I think you are seeing what I am driving home here on this.
My understanding of this forum was to share fun ideas, I have built homemade rides since 1978, I have a degree in electronics and electrical engineering with a mechanical engineering equivalent. The plans are sound as permitted by laws of the date Jul 1964. Even now in the 21st century the same engineering principles are exact. There is one exception, internet can have some jack legged plans that would likely kill someone, popular mechanics no... I just wanted to clarify, the misconception of my intent of posting plans or why I joined this forum.