You can burn the U.S. flag or do anything you like with it: Even use it as underwear. Americans do it. People all over the world do it. And such usage is in fact PROTECTED by U.S. law.
But when we get to the Mexican flag we have much weaker egos to deal with:
"Mexico has complained to Australia's media regulator after contestants on the Big Brother television show threw goo-filled balloons at the Mexican flag as part of a game.
During the show's "Mexican Night" challenge last Friday, contestants dressed in mariachi outfits played musical chairs and ate chili con carne - a dish almost unknown in Mexico - to win points.
One of the rounds of the game showed a team protecting the Mexican flag against slime balloons thrown by a rival team.
The flag displayed the Mexican national symbol - an eagle devouring a snake on top of a cactus - in the middle but had the green, white and red colours in the wrong order.
Source
And how awful not to know what Mexicans eat! The fact that most Mexican restaurants in Australia do serve chili con carne is totally irrelevant, of course.
Even more irrelevant is the fact that I have some good chili con carne recipes up on my Recipe blog. See here. Scroll down a bit.