Hey look, here's a big omnibus article by David Pimentel of the Florida Costal School of Law on all the ways you are potentially legally screwed if you let your kid do stuff that was considered normal at some point in the less intensively parented past.
Even one generation ago, the norms were different for determining the age at which a child no longer needed a babysitter. The expected minimum age for babysitters has gone up as well, although in the few states that have legislated specific ages, the thresholds vary widely. In Illinois, it is illegal to leave a child under 14 unsupervised for an “unreasonable period of time”; in Maryland, in contrast, a 13-year-old is considered old enough not only to care for himself, but to babysit infants. The days when 11- and 12-year-old neighborhood kids were considered competent babysitters appear to be long gone. This development is all the more marked considering that mobile phones have created a virtually instant line of communication between the sitter and the parents, something unheard of in earlier eras, when younger sitters were considered acceptable.
Vague statutes do not provide sufficient guidance to parents to know what matters remain in their discretion, or sufficient guidance to prosecutors and jurors to know when a parental lapse rises to the level of criminal conduct. For parents, the vagueness problem may prompt paranoia. For the legal system, the vagueness problem results in overreliance on the discretion of the prosecutor, on the judge’s attempt to give meaning to the statute via jury instructions, and on the judgment of a jury venire already tainted by media hysteria over child protection.
Via Bryan Caplan, who says "In absolute terms, I'm not worried about being persecuted by child welfare services. But power-mad bureaucrats probably outnumber kidnappers and serial killers at least a thousand to one."