I don't want to discourage anyone from following etiquette, but just a minor point: Etiquette, although important, isn't law.
There have actually been several cases of people burning the American flag and getting arrested, but it's always been overturned. Even going that far in disrespecting the flag is considered freedom of speech.
I'm really glad to hang out with a group like this, where people try very hard to respect each other's feelings because they want to... not because they have to. I wouldn't want to live in a country where someone could be arrested just for being disrespectful.