Compulsory Volunteerism

I thought that this story about a new code making sure that beach donkeys in Britain are treated properly was innocuous up to this paragraph (emphasis added):

The code, drawn up by the British Equine Veterinary Association (Beva) and the Donkey Sanctuary, is voluntary.

Fair enough. Private regulation, especially when voluntary, is always preferable to government regulation backed by legal prosecution. But look at the very next paragraph:

However, owners who break it risk an improvement notice and subsequent prosecution under the Animal Welfare Act if action is not taken.

So, it's "voluntary" as in follow the code or face government prosecution.

Someone send Beva a dictionary, please.