Would this be unprofessional in any work environs??

Here is a question for all of you to respond to.

A person has taken the time to better themselves and get a diploma in Para-education( teacher's aide) In our school division all current and up and coming TA's will be required to have this diploma. Now this person has put their name on the call in list to be a substitute TA. The TA union requires that your name be on the schools list in order to be called in. The person waits to be called in a gets no calls, and later finds out that a person who's name is not on the list has been called in by the school to work. Upset by this information the person writes a letter asking why the other person has been called in (the person name names in the letter) the person also asks if she has the required course and the other person does not why again has this person been called in. Was she unprofessional in naming names or is it the letter itself.

You should also know that the adminstration called the person at home and told very forcefully that she was unprofessional. The person at this time requested a meeting with the admin. During that meeting the admin told the person that they could call in anyone that they wanted. ( not the case according to union rules. ) the admin then sent a letter saying that the persons behavior was extremely unprofessional. Who is truly in the wrong here??