I think it's soothing for a lot of the rest of us but we either don't know it at first or are too stubborn to admit it. I noticed when I got these thick kinda heavy hoodies. I love wearing em, but only works when it's cold enough to not feel hot in em. I need to get a weighted blanket...
Just picturing that in my mind made me feel uncomfortable.
Even as a child, weight or any sort of pressure on my body made me feel trapped, especially in bed. I would start kicking and flailing to get rid of it. I got chastised often for throwing the blankets back.
I understand how and why the weighted works and it's good it exists but... please, not for me. I dread if I ever need to be hospitalized.
This is an instant addition to the weird garden maze thing I've been planning to build for my kid once they're past the crawling phase.
Any further obstacle suggestions that could be incorporated into a tunnel are gratefully welcome. I'm still trying to work out if a ball pit in a box is even a safe idea...
It really depends how your tunnels are built, but ropes going in different directions are probably a good obstacle that could be removed from the outside by untying some simple knots in case there is a problem inside.
Anyways, here is what I typed out before I noticed you wanted to build tunnels:
I think a small bridge made out of a wood frame and a net could be interesting.
By having the net hang in a U shaped cross section the kids can't fall of to the side, while allowing you to help out from above.
If the net is hung loosely it softens falls and keeps it a challenge as they grow, but it might be difficult to traverse for small children.
If you want it pulled tight I recommend some parallel ropes at the bottom to walk on.
Also a tilted plane with wooden holds or a knotted rope.