Danger in the Woods ahead

If I was walking along and coming up on some beautiful peaceful woods and just inside the woods there was a guy there who said "Be careful, Danger ahead - I was just in there and there are bad things afoot. Be really careful." I would say wow really? thanks dude and proceed on my way with caution. Somehow when I tell my kids to be careful and pay attention and watch out they just look at me like I'm an asshole! My sons are 6 and 9 years old. I tell them don't do that again or it will mean certain death and they do it again anyway. My 40+ years of experience has no bearing what so ever on them. I don't get it at all. I wish I could somehow make them see my point of view for just a minute or 2 instead of having to wait 20 or so years until they are parents for them to think - oh so my dad was right. Damn! bummer!