While it is entirely possible that anyone at a pool or playground could be a child’s relative or guardian, it is important to at least keep an eye on anyone suspicious. I often take photos of people, in case I feel it necessary at some point to contact police.

This is not paranoia, nor is it going too far. If you have any idea what some people are capable of doing, you would just do these things naturally, as a part of your routine of taking your kids out to public places.