When people talk about a "non profit" entity, they are almost certainly referring to a legal non-profit. Maybe that's not what GP meant.
And yes, you are technically correct in that there's no way to know that they are or are not pulling in money and pocketing it. I'm not sure how that's relevant to the questions asked but okay.
There is. Without a legal framework its just an association that claims not to make a profit. This is all word games though as be clearly don't agree on the definition of a non-profit organization.
In UK there is simply no such status as "non-profit", so technically none of what you listed are "non-profit" organizations. These are unincorporated associations, that, by the way, can be making profit (but that would be on shaky grounds, since common law makes it hard not to fuck up, being as vague as it always is). However, there is a "charity" status in UK, and you'd have be a registered organization to obtain it.
Anyway, "non-profit" is (i.e. "only makes sense defined as...") a legal status, it isn't just a way to say "not making money" (after all, we wouldn't call any failing business a non-profit, right?), so it really doesn't make any sense to ask if an illegal underground gang is "non-profit". GP is correct to point that out.
How do you know?
> and there's simply no way to know that they're not taking in loads of money and pocketing it.
Or that they are, right?