I agree, it is extremely important to tell your kids that if anyone ever says “this is our secret don’t tell mommy or daddy” that is the que to immediately tell Mommy and Daddy. The only secret they are allowed to keep is if Mommy or Daddy are buying a birthday present or making a party. Any other secrets they MUST always share with Mommy. If anyone tries to convince them otherwise then they are probably evil people.
I also tell parents that after pre-school when there are 3 morahs in the room, teach children that they are NOT allowed to sit on anyone’s lap. And if the teacher or the Rebbe ask them to they should simply say “my Mommy doesn’t let”. That should be enough of a warning to anyone.
In addition, let them put their hands in a circle in front of themselves and teach them, “this is your own daled amos, your own private space. Don’t let anyone get too close to you that you feel uncomfortable. If they get too close, into your space back away and even run away if you have to. If anyone wants you to be alone with them scream, don’t go anywhere alone with even someone you know even if they said Mommy or Daddy said. Teach them to shake hands with the teacher or Rebbe instead of accepting a hug or even a pat on the back.
I also tell parents to put their cell numbers in the child’s coat, shoe, knapsack and anywhere the child can easily find it. So if someones says “Mommy told me to pick you up” they can say give me your cell phone so I can call mommy and ask her”. Molesters will back away from SMART kids and kids that are prepared to fight them off.