I'm sure you can, but what would it cost to buy appropriate netting material? Gotta be small enough holes so fingers won't get stuck, strong enough to the little tyke won't tear through it, secure enough so he/she/they won't go under it or over it.
On a side note, I once saw a motorhome being built with a basement for children to play and sleep. How cool is that?
Just my thoughts from a grandpa
BTW......