I was recently exposed to a photographer of a different ilk: essentially a bully, this guy used a referees whistle to control crowds, pushed and shoved his way around, and, when told he was out of line, resorted to ridiculous lies and profanity. He was a very unprofessional photographer.
The etiquette of photography is, like all social etiquette, a dynamic set of behavioral expectations based on The Golden Rule. I say that it is dynamic because the situations involved are so varied. On the sidelines at a professional football game there is an expectation of competitiveness; at a funeral there is an expectation of reverence; at a crime scene there is an expectation of preservation of evidence; and so on. Above all these expectations is an expectation of respect, and I have always made an effort to show respect in all my photographic journeys, be they at a junior high football game, a home destroyed by fire, or the fragile majesty of the desert.
Many photographers have huge egos, and as a result they adopt arrogant postures in their behaviors. Ultimately, of course, this kind of behavior damages their reputations, and the reputations of those they represent. In your travels to make pictures, don’t forget that you represent a community of artists. Do unto others as you would have them do unto you.