This doesn't mean the category is necessarily invalid, but it does prove the importance of remembering what kind of category it is.

One applied from the outside and in ignorance is, I would suggest an invalid one and more importantly a unhelpful one.

My local Licensing Manager has visited an unpaid participatory session and in their ignorance has placed it in the category of public entertainment and the customers n the category of performers.

The point is that this person placing me in this category is never going to convince me that under those circumstances I am a performer.