I'm a survivor of childhood sexual abuse. I thought long and hard about this and decided that talking to my children about the existence of sexual predators would rob them of their innocence.
I've studied how this works. Sexual predation almost never starts with rape. It starts with myriad instances of boundary violation and disrespect and culminates in rape.
Rape hinges on the detail of consent. As a society trying to combat this issue, we seem to overlook that for the most part.
I taught my children that hugs and kisses required consent. I taught that from birth. Even a baby too young to talk can turn their face away because they don't want a kiss or hold their arms up enthusiastically to receive affection.
When they were older, I told them if they told someone "no" and their decision was not respected, come get me.
I only had one of them come get me once. The person who felt entitled to get "sugar" from my child was utterly shocked that I told them they were wrong.
This was an elderly female relative. My children are both boys.
Most likely, she wasn't actually a child molester, but this practice of adults demanding hugs and kisses from children who have no right to say "no" is commonplace and gets treated as something funny in movies. I treated it as no laughing matter.
If you want children to understand consent and respect, the best thing to do is let them experience it firsthand from birth. And make sure they know that rule is a two-way street, not a one-sided privilege.