Answer:
A trade union gives a professional businesslike view on current labour dealings with a company. Often an individual is not verbally skilled to do this so management perceives this to be naivete and not important input to decision making for the company where as union officials are professional negotiators
At minimum it at least shows the concern of the people who work under a manager
Weather decisions need to be tightened loosened or the managers ability is put in question will be examined and hopefully an improved outcome is reached