Hi, most of the police websites that address this issue focus on messages that empower children when they are approached by someone they don't know, are offered something, invited to leave somewhere or are upset by unfamiliar people - adults as well as other children, males and females alike.
There are fewer issues with children approaching adults where they are in sight of a parent or carer.
It is an awareness of just how damaging people can be that will keep you on top on this xx. Can you note what it is that you are truly worried about - abduction, abduction from where, child taking off on you, you needing to catch or keep up with them, a child taking off and becoming lost, you failing in a duty to protect them, a child being abused, threat of abuse, is there a sense of helplessness or fear as a professional that you could lose control.
Ask yourself what harm a stranger can do at the time the child approaches them and what the benefits are for being able to communicate freely now and at all stages throughout a child's life. Risk assess by looking at where the child approaches others - a bus stop, in the road, at the park, is a stranger likely to follow up the contact on another ocassion, is this a risk, or a pleasantry promoting community.
Identify all the times the children are out of your sight and ask yourself why they're out of sight.
Encourage disclosure, talk about the day's event, who was happy, who was helpful, who was upset, what were everyone's feelings for the day, ensure children know who is picking them up from somewhere and what to do if that person isn't there.
If you can, really enjoy the social side to your mindee's confidence and maybe organise some planning that'll help you overcome the fears. Your mindee will discover that not everyone responds to a child's attention in the same way which often prooves to be a natural recourse for discussing how different people are and how a child can react when the greeting isn't quite as open as they expect.
Chat with your parent, ask them why they aren't as afraid for their child as you are.
Keeping children safe resources on nspcc
I hope this helps, best wishes xx