Just yesterday a neighbour mentioned to me having been surprised to see a bare bottom through the open door of a unit. We had a bit of laugh about wording of a vague, euphemistic, mock-serious item “Residents are reminded that…” to put in the newsletter that could be amusing for inviting more speculation among the local gossips than the original event warranted.
More seriously, I don’t think there is much you can do about your more casual neighbours if they are staying within the bounds of the law.