This topic should of been in 'General'.
Whats the use? I don't think she should be banned, especially since, most likely, she's not comming back. She was just mad at the moment, and if she was mature enough (Highly doubt she is though), she would get over it and move on by now. If it happens again, then I think you should talk to Rizz and see what he thinks about the situation.
My advice to you is probably not to hold anymore contests? If it cause this much trouble, I think that it should end. Last time somone started a contest, I had a complaint where a visitor said that, she one 1st place and her front yard was spammed with dolls and plushies that she didn't like. Not to mention she said she didn't enter the contest. .-.; So, not only contest is a stress to staff, but to visitors as well.