About 97% of all abductions are done by people the child knows well, usually a non-custodial parent. Molestation is also primarily done by a trusted adult or another child. Instead, make a secret word for when you need someone else to pick up your child, discuss rules like no going into ANYONE's house without telling you, tell them to seek another parent when lost, teach good touch vs bad touch.
"When you assume the worst about your child, the worst is often all you can see. When you assume the best about your child, they tend to live up to your expectations. Assume the best intentions and the best motivations to grow the best parent/child relationship." L.R.Knost www.littleheartsbooks.com