Every time you meet a stranger you always qualify this person as good or bad. You cannot be blamed for doing so because this is a natural behavior especially if you are dealing with strangers who you know nothing about. If you have a gut feel about someone, that he is bad or evil, the easiest reaction is avoidance. While if you sense some goodness in this person you are trapped in making a decision on whether you open yourself to this stranger or stay away. At this stage you are bound to become anxious because you do not know whether to go right or go left.
This is the position where you put your kids if you scare them about strangers. They will always feel anxious as they need to come up with decision on something that will need their judgement. For some regardless of their gut feel, complete avoidance is the answer. That is very true and very easy to do. However, there are many clever nasty people who know how to manipulate and take control. They will fall into the good category that will give them a fifty-fifty chance. Children are easiest prey as they are easily swayed or easily coerced to do things that they may not even like doing. Curiosity is sometimes the other reason where they allow themselves to be manipulated.
Helping your child to obey house rules in internet usage is the best thing to do. Keep your rules simple, detailed and clear that young children will be able to understand. Keep in mind that you are not only preventing them to be anxious you are also protecting them from possible internet abuses.