Laws about alcohol promotions?

I currently work for a major brand beer promotional team in Wisconsin. I just found out today that one of the girls on my team who is also promoting this beer is only 20. She has been working these promotions for 4 months now. Samples of this beer are being served to her at our meetings as well. Does that count as serving someone who is underage? Also, isn't it against the law to work beer promotions until you are 21? If so, what will happen to the distribution company she was hired through if someone finds out? One of the other girls is planning on reporting this.