As long as X is an adult citizen, the first answer to any question "Should X be allowed to vote?" is YES. The second answer, depending on the context of the question, should almost always be either profanity or violence against anyone that answered NO.
edit: Of course, there is a conflict of interest with public employees' unions. The issue there, is that public employees should not be allowed to unionize in the first place; they can engage in their collective bargaining at the ballot box. It'd be like a private corporation having an "shareholders' union".