I don't think you need to fear the Highway Patrol officers. They are usually very polite, even friendly and helpful in most situations. As long as you treat them with respect, you should have no trouble. If you are rude, drunk, or insulting to the police, they might become angry and arrest you or charge you an expensive fine.
You will see many cars with Ontario or Quebec plates on the way to Florida, and at most Florida vacation attractions. Most people in the USA are friendly to all foreign visitors. Naturally, there are some punks, like the skinheads in Europe that dislike anyone that is different. They typically hate blacks, Mexicans, Middle Easterners and possibly anyone speaking another language. Normally, you would not find these bad guys in the areas frequented by tourists. The police would chase them away.
These bad guys would be found in the poorer neighborhoods, where crime and drugs are common. Those are not areas where tourists normally venture. I think this is true in cities all over the world.