[Zhiroc]

The problem I foresee is that it doesn't add information. Who gets to call themselves a professional? Does it mean run by a for-profit company? Would most open software projects be therefore called hobbyist organizations?

If we can't agree on the term "free", there's no chance we'll agree on "professional".

But since it's a content-free term one way or another, and people can choose which they want to call themselves. I don't really care. Might as well add it if it makes adding the payment information more palatable.