It happens in the US too. I was shooting a documentary in Louisiana one time, just 2 people crew using DSLRs and got stopped 5 times a day for a week by police, sheriffs, private security, random rednecks with guns. Always shooting in public places, and always shooting fairly boring things - buildings, streets, rivers, wildlife etc - never even shooting people. We weren't scruffy or ethnic or anything. Always talked our way out of it by explaining the whole project but we got threatened many times. My favorite was the private security guy who came roaring out because we were shooting up a river, from a bridge, and there happened to be some sort of fuel storage somewhere along the river in a line where we were shooting from. Said he was calling the sheriff and to "not move a muscle" with his hand on a gun the whole time. I gave him the card of the sheriff, who had just given us a river tour on a police boat and just said "here's his number - I'm sure he'll remember us as we just left his office an hour ago."
Honestly don't have too good of an impression of the South.