Accept nothing they offer you without cause. But if you do them a kindness, without thought of recompense, and they offer a gift in return regardless, then it is generally safe and likely beneficial. Generally— exceptions do apply, particularly in the case of user error or suddenly getting really greedy with the gift.

Errr… this applies to the fae, but not customers, I guess. Perhaps the analogy is not perfect then.

Let’s say they were organizing using telephones instead. Would you want the telephone providers to proactively listen in on their conversations and cut them off based on content? No. You get the police or FBI to investigate and hunt down the people, possibly with warrants obtaining information from the telephone companies, and target the people doing the crimes.

I feel it should be exactly the same with ISPs. The ISP shouldn’t be doing the policing, the police should be doing the policing. The ISP’s job should be passing bits from MAC address A to MAC address B, nothing more.