Confederate Flag on School Grounds

Hey y'all. So at my high school, everyday as soon as school is over, these kids pull a Confederate flag out of their beat-up blue pick up truck, and either put it on a stick in the bed of their truck, or someone sticks there head out of the passenger seat window and waves it out. They also enjoy yelling profanities at people while they do this, particularly a rather offensive word to gay people. They then proceed to ride out of the parking lot, causing a commotion, and all around just pissing people off. One of their group isn't even in high school anymore; he graduated last year!

So my question is:

Should I report them to the school? And if I do could the school do anything because technically it did not happen during school hours? (Though it did happen on school grounds).

You can say it's a historical thing but since we live in Central Pennsylvania and one of the kid's got suspended last year for drawing Nazi swastikas and calling someone a derogatory term towards gay people, I don't think it's a historical thing. Call me crazy, but I don't think that's the case here.

If yes, any tips on talking to the office about it?