It’s a small and specific part of your player agency but I agree with you that the lack of stated conséquences takes away your ability to make a choice as a character.
im fine with it because I’m the kind of DM that likes the latitude of this imprecise rule, but the PHB is of no help here. For all we know, you’re simply kicked out of your circle and may longer benefit from the organisation you never cared about anyway…
My interprétation, which has no foundation in RAW in any ways, is that wild shape is an ability that allows druids to « wear » the skin of animals (or other form) as long as they don’t wear the skin of a metal-clad warrior. To take the form of animals, animals must be their armor. It’s a Celtic-like geis, if you violate it, you lose your wild shape. For how long? I don’t know. From a moon (for a minor offence) to permanently ( for a careless and regular use)