My next door neighbor is English. Apparently, in England, when the police stop you, the practice is to get out and walk back to their car. He got stopped by an American police officer and did that, honestly not knowing any better. The policeman, obviously not knowing what was going on, was totally confused, and pulled a gun on him, leading to more misunderstandings. Things got sorted out, but believe me, he is very, very careful any time he sees a police car.
On a tangentially related note, I got stopped one night about 1am by an officer who wanted to tell me I had a headlight out. We chatted, and I gave him my ID. When he came back to the car, he was a changed man. He didn’t come all the way to the window, but stopped at the back of the car, pulled a gun, and ordered me to put my hands on my head and started asking me a lot of questions about myself: name, address, social security number, other cars in my name, had I ever had another driver’s license, etc. It turned out that there is someone out there with my name who is considered armed and dangerous, and has been known to shoot at police officers. It scared me half to death: we were in the middle of nowhere, it was late, and the possibility for tragic misunderstandings was huge. I convinced him that I was who I said I was, and harmless, and he was very pleasant to me. After I calmed down and drove away, I realized that the officer probably went through that two or three times a night. If I were he, I would stand way back and draw my gun, too.