Does it violate employee obligations for loyalty and discretion toward the employer?

Canada: Union Message in Work EmailIn Canada recently, The Court of Appeal of Quebec supported an engineers’ union that filed a complaint after its government employer prohibited members from adding a labor message beneath their signatures on work e-mail.Before deciding they can ban employees from including union messaging under their electronic signatures, employers must consider the factors the court considered in this case. Is the message factual and respectful? Does it violate employee obligations for loyalty and discretion toward the employer? Does the message harm the employer’s reputation or business?Below is a link to a related article:http://www.mondaq.com/canada/x/836606/employee+rights+labour+relations/Employees+Use+Of+Employers+Email+System+To+Send+UnionRelated+Messages+In+A+Collective+Bargaining+ContextPlease consider these questions:1. Would this be permitted in the US? 2- 3 bullets point2. Should unions be able to access and use employer computers and email for purposes that may be opposed to the employer’s interest, for example during collective bargaining?