Originally Posted by
polonius
As Christo's works reveal, people in positions of authority don't respond to things that look like potential criminal activity, but rather to things that are outside their narrow experience. Seeing two workers hoisting a giant piece of pink fabric to cover a tree can hardly be mistaken for criminal activity of any kind, but I guarantee you it attracts police attention, because it is an activity outside the conventional existence those police officers experience in their conformist suburban world.
Non Devil's Advocate comment:
When things are out of the ordinary it is a cop's duty to check it out. They have no excuse if they are rude about it, but a polite inquiry is warranted.
If something unusual is happening and the cop ignores it and it turns out to be something illegal/dangerous the cop has shirked his oath to protect.
Take your artist, someone wrapping trees with pink fabric could be a prank and not an "art" exhibit. If a cop does not check it out then the owner of the tree wants to know why the cop did not stop the vandalism.
I am a hobbiest photographer, and I have found that not only cops are curious but the general public is too. When approached by a cop asking what I am doing, I tell them. No skin off my nose if they know I am shooting a model or building. Sometimes they will point me to a better location.
If the officer asks to see the photos because he like pictures or is interested in photography, I will show him if I have the time. (models cost money) If he demands to see the pictures because he wants to "investigate" my intentions, then I tell them to get a warrant.
What I have found in most cases with cops and the benign unusual situation, like a model shoot, is they are just talking to you to break up their boring day.