In parts of Southern California it's illegal for unlocked guns to be left where minors might be able to get to them and recently a few dads were charged with breaking that law after police searched their homes. They now face serious jail time and fines, even though it's extremely unlikely their guns would have ever been used criminally.
Most people I know who hunt and shoot regularly have a lot of guns and many who have older kids, like the 17 year old in the story I provided a link for, have been hunting and shooting with their kids for many years by the time they are 17. Most quit locking up their guns years ago, after they became convinced their kids knew the rules and how to handle them safely.
In these cases someone claimed the minors had made threats, prompting the police searches of the parents houses.
The reasons laws requiring firearms be locked up have been transitioning from simple safety, (we don't want a child to accidentally shoot one), to our fanatical desire to make guns totally inaccessible to criminals. Millions of gun owners who regularly shoot with their kids don't just have accessible guns, their kids own guns. My parents gave me a semi auto 22 rifle when I was 12. I began reloading bullets when I was 13, and was camping by myself and with friends in bear country with a 357 when I was 14. Half my friends and their kids bagged their first deer before they were 16.
Lets face it most kids can buy a hacksaw at the 99 cent store and cut the lock off a gun by the time they are 14. Throwing a dad in prison because they have an unlocked gun at home is a standard that only makes sense if we are trying to criminalize more gun owners, even those who have done nothing wrong. Kids say stupid things all the time, that doesn't make their gun owning parents criminals.