I know it does. It doesn't make what she did illegal. She was not preventing anyone from doing anything, she was not violent, she did not damage property, she wasn't there when it was closed, and it was open to anyone else who wanted to be there peaceably at the time. Bad arrest.
If they ask you to leave and you refuse, it’s trespassing. Doesn’t matter if they are open, etc, etc.
Now, you could go back and sue them and probably win if they had no reason to ask you to leave, but you have no right to resist arrest simply because you think you should be allowed to stay somewhere when they are asking you to leave.