The unions have crazy complex pay rules. For example, in the private sector, if my boss goes away on a 2 week vacation, usually the boss might delegate someone

The unions have crazy complex pay rules. For example, in the private sector, if my boss goes away on a 2 week vacation, usually the boss might delegate someone to answer questions and possibly run meetings... but that delegated person doesn't get paid more. However, the public sector unions have negotiated that the delegated person get a pay bump for those 2 weeks only while the boss is away.