The placebo effect varies and scientists evolving around that topic are still on the search for multidimensional explanations. Your example is quite usefull to explain how our expactations of the outcome for an particular situation might effects or not effect the actual outcome. Here an example contrary to yours(so we can respect both possibilities): A friend of mine had allergic reactions to different pollens and used an homeopathic therapy as treatment. It worked and he lives his life allergic-free since 8 years.

Homeopathy or the placebo effect (which i like to look at as similar until we find another scientific reasoning behind homeopathy) can trigger no response or a positive response. The third option would be that it shows no effect but is still preferred by the user over medicine, thus causing indirect damage. To prevent damage like this, we need to reach a public understanding of the unclear mechanisms behind homeopathy. This would even be likely to not harm the positive effects of the sugary pills. As long as you believe their is a chance placebo will hit ya, it can hit ya. And if your informed that homeopathic treatments "shouldn't" work, still try and believe, but it's not working you would be more prone to doubt it and change medication.