I was left home a lot when I was a kid. I was out in the country and of course, it was before cable television and we only had black and white movies and soaps. I was bored, lonely and I found ways to amuse myself that would never have amused my parents.
I have 4 daughters. I have never allowed my kids to be out of my site for long. Even as careful as I was, my kids have told me about times they hurt themselves and hid it from me. One daughter told me that she scraped so much of her back foot off that she thought she could see bone under a flap of heel! I hope it wasn't that bad. She's almost 19 now and she was only 8 then. She said she felt that we had to spend too much taking her to the emergency room because she was always hurting herself. She said she wrapped it up and kept her socks on around me until it healed.
I did the exact same thing several times when I was a kid! My parents would have freaked a few of those times if they had known.
My answer is no, she's too young. Dad needs his sleep and he shouldn't have to wonder what she's up to.
BUT... that said, many of my daycare children have been in this situation when they slept at my house overnight and stayed home with the parent that worked graveyard. They did survive. But their parents told me about the arguments they had when they ran off, left the house, messed up the house, tried to use the stove and all kinds of things. They still have survived.
Suzi