Indeed you can go very wrong by not doing so. Medical ethics is a balance of risk and benefit, not "What is best for statistical power?" Equipoise is required for trials, and is often a precondition of being able to do studies in these settings.
Heck, a lot of recent work on novel trial designs like stepped-wedge are specifically designed to balance equipoise and statistical needs.
Heck, a lot of recent work on novel trial designs like stepped-wedge are specifically designed to balance equipoise and statistical needs.