I think it was the Mexican comedian Mencia who said "there are more kegs than kids at a Mexican kids birthday party"....
So it truly IS a cultural thing....I was dumbfounded by my in-laws having their daughter's quinceanera (similar to sweet 16, only at age 15) at a BAR!!! They did rent the entire thing, but still, my feeble American mind just can't comprehend the idea of having a 15 yr old's birthday party at a cheesy, hole-in-the-wall, fully-stocked bar. Oh, did I say my in-laws were from Mexico?