I have been going to a bluegrass jam at the Oak Park Farmer's Market for years, when I can (which is about once a month, and often not for more than an hour). We go as a family and Nico fixates on the music, because he truly loves music and dancing, especially live music involving guitars and fiddles and the like.
I rarely bring my guitar, because carrying a guitar while dealing with the two kids is hard, but a friend who also plays banjo is usually willing to lend me his. When Nico was little, he would sit still, snack, and listen for hours. As he's aged, his attention span drifts and he wants to wander a little, but he always returns to the music.
Especially when the music is outside (weather permitting), there are dozens of children, scattered around the edge, but Nico usually walks carefully into the middle of the circle and starts to dance. It's almost never been a problem. First, if he does lose control then I'm right there, but he doesn't. And people just accept his presence. They understand, I think, that in the middle is where he needs to be, that including Nico requires a different level of rules and management than one could do with a typical child. I could stop Nico, and do when he needs to be stopped (out of control, tired, hungry, etc.). There are lots of rules for him, but the line of "don't stand and dance in the middle of the musicians" is not one I need to draw.
That said, if every parent made the same decision, there would be too many kids in the middle.
I have no idea how this works. But it does.
Nico dances in the middle, both carefully and filled with joy. It works.
It's inclusion - not equality, not same-ness.