My response:
Not naming who she was tweeting about brings some legitimacy, but when she specifies the performer's audition ID number, and factoring in the real time aspect, makes it rude. But I don't think, in a world that celebrates Simon Cowell, that she was obligated to reach any kind of agreement with the actors union. She should be allowed to express her thoughts, perhaps after a set of auditions are completed. Her mentioning of free speech, however, is legally sloppy, as no government supression of expression was involved or threatened. As for the parallel with interviewing, I'm not sure I buy that they are sufficiently similar processes to then extend the confidentiality of interview results with audition results. Regardless, I should be allowed to tweet my thoughts on limited elements of an interview, so long as I protect the identity of the candidate, including the timing of the tweet.
I later added:
Auditions are not the same as traditional job interviews, and confidentiality should not necessarily be applied to the same degree, simply because what is expressed during an audition is by definition intended for a potentially wider audience. Of course, performers who audition deserve courtesy and respect, but I am not yet convinced it's just the same as interviewing.