Ok, can you write a law that allows those things while disallowing "leave my 8 year old at home for a month while I go on vacation"? Where are you going to draw

Ok, can you write a law that allows those things while disallowing "leave my 8 year old at home for a month while I go on vacation"? Where are you going to draw the line, and how? Do you think you can get a whole state to agree with you on where the line should be? Does age matter? If so, what ages matter, and how? Do you think public attitudes might change in the future, and require the line to move? The only way to write this law would be to provide basically no guidance and give police and judges and enormous amount of discretion, or to provide a lot of detail that includes concrete examples of things that are allowed and things that aren't. The world is too complex to write this in purely general terms and expect it to work without issue.