Well, I'll tell you -- they showed how these kind of "chats" get sexually explicit very quickly by the predator. There is nothinig subtle going on here. So, if your kid feels uncomfortable with something a person says online, that's a big clue something's wrong and more could go wrong.
As I posted to you earlier, teachers in the gay straight alliance and in sex ed talk dirty to the kids. They also use sex surveys to introduce and numb kids to inappropriate prying from adults at school. It makes kids numb to the danger and to the inappropriateness of adults -strangers, essentially - getting involved in shaping and prying into their sexuality. It is so dangerous and wrong that we have let them disolve the taboos of adult/child sex. Also these teachers are of the non-judgemental sort - they claim it is "hateful" to judge any degree of adult sex tossed at them in images or in voice.