You almost never hear of people on the beach getting angry when a guy or girl sets up a camera in front of them. I do however see the analogy to a surfer dropping in on your perfect set.
Sunsets are a little like that perfect set. There may only be a brief few minutes where the scene is just perfect.
After watching this woman for a minute or two I came to the conclusion her telephoto lens would not notice my intrusion so I dropped in on her.
Photo: Robert Rath, 'She Takes Photographs, 1/160s f/16 ISO100 15mm