I read the article, and it didn't say that she was actually banned. The article stated that this was a decision mutually agreed upon by Prince William and Catherine.
Incidentally, I also read the other article concerning the striptease surprise. It said that William and Catherine attended a party being given for the charity named after Henry Van Straubenzee. The striptease was a part of the entertainment at charity party, it wasn't at a strip club.
I would assume that it wasn't a real striptease, since the person doing the stripping was a female impersonator, and a lot of the guests at the party were of an older age group than William and Catherine. Henry and Thomas Van Straubenzee's parents were there for starters, along with their friends.