If you know any mexican people then you'll know this is a non-derogatory term used to refer to US citizens. Mostly because the term "American" does not make sense to the rest of the Americans (all those people who live in the continent named "America", wich is every body from Alaska to argentina), and the word "Estadounidense" (UnitedStatean)is too long.
Folklore says it was generated when the US invaded mexico, wearing green uniforms, and the people shouted at them "Green Go Home".
With time it lost all derogatory status and was turned into the most common word to refer to any US citizen.
The high school where there is absolutly no parking. Where they build a Junior lot that fills by 6:50, and where the cops get tingly feelings by tickiting you for being in the no stopping no standing zones even though there is no other possible parking. The high school that you pull up to a half hour before homeroom starts, and cringe as you realize there is not a single space on either side of the road, and the neigborhood is full...you say a few words of prayer as you pull in front of the no parking no standing sign, hope for the best only to walk out after 13th period to find a $125 ticket placed ever so elegantly under your wiper blades. Cherokee, the school that takes pleasure in using huge orange cones to block off what little parking we do have; the school where you wish your friends would just fail their license tests so they don't hog up your potential parking spaces.
I have received 5 tickets in the past few months for no parking no standing. The announcement made today: "Students, we need to keep a good relation with Brush Hollow, don't park the wrong way...dont park there at all..."
Best example, the HUGE, pointless orange cones.