One of the difficulties in trying to start up such a thing would be compliance (even though voluntary in this case).

Same goes with an industry "best practices" or "code of conduct" kind of thing.

I think it'd be extremely difficult to get people to agree to comply with it, precisely because there's no guarantee everyone else would comply with it. Even if someone knew and was fully committed, on their own, to be thoroughly upstanding, they might feel at a competitive disadvantage compared to those webmasters who wouldn't agree to any such thing.

For example, even if you had every intention to never shave, you might not want to volunteer yourself to some 3rd party that would monitor you making sure you weren't shaving when there were tons of websites out there that weren't monitored by the same body.