Sadly, this is true:
Now that I have a kid, I’ve noticed that most parents think like this. They believe children are safe only when they are in the care of adults, in part because kids have to be protected from would-be pedophiles and abductors. But as a psychologist with an expertise in child abuse, I can tell you this theory is hogwash. It’s exceedingly rare for a child to be taken by a stranger, and in around 90 percent of sexual abuse cases, the perpetrator is someone the kid already knows.
Most often, that someone is either a family member or an acquaintance, such as a coach, counselor, priest or teacher. So ironically, when we put our kids into educational programs and organized sports to keep them safe, we may actually be putting them in more danger than if they were just playing outside with their friends.
The reality is that you cannot possibly be there to protect your child 24 hours a day. At some point, they will be somewhere else, with someone else. Better to help them develop the confidence to talk to you about anything, and say no to adults than to let them be easily influenced by people who wish to do them harm.