Hopefully no parent would hire a sitter without fully checking them out and asking for references. But I think some of the adults have hassled this young person as much as she has given back. She is a child, I think that needs to be considered.
Teenagers are sometimes very reactive if you back them in a corner. No excuse for rudeness, but then some adults did not learn that lesson either.
Just my 2 cents, I am sure others will vary.