If people want this for medicinal purposes (which I do believe there are), it probably should be under professional supervision imo. Obviously it's plenty possible to do it solo or with friends, but the more people do it, the more dumb people who will make dumb decisions or take too much and freak out, and that won't look very good. On the plus side, it's not a substance people get addicted to.
All in all, freedom move :*
Last night "someone I know" took some psilocydin in a pill for. The said person had a very fun time and was in control of himself completely at about three grams. The comeup was strong, followed by a prolonged lull, followed by a pretty decent peak and subsequent come-down. Legalizing the substance at ~4 grams or so should prevent people from taking too much.
Of course, an inexperienced user taking ~4 grams would probably still lose their mind for six to eight hours. So who knows, maybe my point is moot?