What I encounter is people who apply etiquette from one water they fish to the next, without considering any local factors such as size of the water or regular fishing pressure. For instance, on the San Juan in New Mexico, it is common, and accepted, to fish quite close to someone. As in, your drift and his almost overlap. On the lower Dolores, "too close" for me is a quarter of a mile.

Err on the side of being too polite.

Blackwater, I would not put a flyer on someone's car. To me, that might as well be littering. The wind gets hold of them, people get annoyed and throw them away, it rains on them...