Privatization of public spaces

Seeing some of the examples of social art from this week’s module, particularly the sculptures in the first half, I noticed how many of them (like Calder’s flamingo in Chicago) were on privately-owned public spaces. I also ran across an article this summer on how publicly owned spaces in major cities are being sold to private companies. Does this change the type of public art that people can make? Does private ownership mean that spaces are more closely policed than they might be under public ownership?