This is absolutely 100% a question about state law, and the answer will vary state by state or perhaps even in some places by city. As will patterns of enforcement.
I work with model train layouts. At one convention hall, we were allowed to assemble our layouts (bolts and thumbscrews; everything pre-drilled), but couldn't use a hammer. I was curious-- could we have used a large wrench to encourage things into place? It wouldn't have been a hammer...I was installing some security equipment in a machine room at an AT&T facility 50 or so years ago. I was allowed to plug in phone wiring to my equipment when there were connectors on the end, but to fasten two wires to a screw terminal strip I had to wait 3 hours for the staff union electrician to come do the job.
And let's not get started on convention halls.
That's ridiculous. No one but owners and fellow modelers should handle model train layouts. That'd be a deal breaker for me if someone had an issue with that.
Union shop.
