I am in need of legal counseling. If I want to go inside of a private business and just start shooting pictures do I have the right to do that until someone asks me to leave? Obviously I wouldn't be taking pictures in a bank, federal building, or courthouse etc... but rather in corporations that I stand firmly against (think Walmarts, McDonalds, Starlessbucks, etc...). I want to photograph as an act of protest by angering the customers and the establishment but also by possibly getting decent shots of incriminating conduct (obesity is the 21st century tobacco epidemic!).
So my question: can I take photographs in private establishments until they ask me to leave or do they have the right to arrest me once I start shooting photos? Obviously if there is a sign posted saying no video/photography I would understand being arrested on sight but I am ignorant to the law of walking into a Walmart and taking pictures of employees, customers, etc... and making everyone uncomfortable.
Please help. :)