Jumping headfirst into the deep end of a pool is not a good idea unless one knows how to swim.
I think a lot of that has to do with the fact that many newbies don't take the time to research the herbs before they use them. They see an herb's properties or healing capabilities and jump to using them without any further research.
Most of us state that they should research first or talk to a medical professional before using any plant or herb for both their safety and ours. If you give a youngster information and they act upon it, and you neglected to post any disclaimers or warnings, you could be liable for any injury that occurs.
That said, I think herb work is a wonderful area of study and I think individuals should look into it, if they are interested in learning more about it. However, I believe they should only work with something once they have the proper knowledge and experience of working with the plants. They need to study the herbs or plants in question and triple check (if not more ) their sources on the plants uses, possible toxicity, possible allergens, etc before ever working with the plants or herbs.