My initial thoughts are that it will be a free entity. As per local regulations in Europe, this can't be a tax exempted enterprise either. So basically a cooperative or a private business with a non profit charter.
You make an interesting point - I never thought about advocacy groups and the PR risks they might carry. I was more thinking about end users/consumers and private businesses. I suppose that is a risk you carry irrespective I guess - even if you were a private, for profit business.
Where was your non profit ISP based if I may ask?