Because the waitresses wear this outfit. Oh yeah, the beer kicks butt, too.
[EDIT: I'm not the only one who enjoyed the costumes, as is apparent from this posting on craigslist:
I just wanted to give a shout out to the super freaking hot NXNW Octoberfest ladies working at Octoberfest last Saturday. The beer tent wasn't the only one pitched that day. Thank you for making it THAT much better. We'd also like to give a shout out to our friends the wind and your very cute panties. It was certainly a day to remember.]