It cant. Because bad employees are subjective. I worked for a company where my managers routinely felt I was one of the hardest and most respected workers on my staff. One month they hired a new manager. That same month I got employee of the month. A month later I was told by this guy he didnt like me, he felt I was unprofessional and he thought I should be fired. My AGM looked at me, looked at him, and was like "Um....are you sure you got the right guy?" Unions cant be that way. They have to fight for every employee. This way the best employees know they will be protected if even the worst ones are.