I have always found reassurance in the following process. Be certain that all family members or close friends that may have your child in their possession for any length of time are always refreshed with the advice that they never let them out of their sight for a second. Also, don’t allow them to take the child to public places unless you have established trust with your loved one’s ability to focus on your child and their safety.
Buy a leash. My sister has been using them on her kid’s for years. Though I had to warn her against the dangers of a flea collar. Just kidding. They work in busy places.