Yes, just think about that everything is owned by anyone. If you had to have a release for anything, there wouldn't be any way for photo journalists to work. I once heard a story about this lady talking to a group of young people, hanging out, chatting with eachother in some small town. She asked if they would like to be on the cover of a magazine, and ofcourse they said 'sure!'. So when they went to the store to get a copy of the mag, they saw themselves on the cover with the text "How to control young criminals" :)