I work at a fairly large private school in both the IT and library departments. Myself and four other people make up the IT help desk, providing computer and audio-visual help for those that need it (usually walk-in). Our duties also include supervision of students at recess & lunch when they come in to read or play games
The five of us are managed by a person who is essentially Jen from The IT Crowd -- she knows nothing about computers, but manages the library, and, by extension, us. She's also a part time teacher. She is very inconsistent with the rules, usually ignoring them or overriding them when the mood strikes
For example, if students don't have a laptop (because it's getting repaired by a third party), they bring in proof of repair and we give them a laptop to use until theirs is fixed. The rules are very straightforward and are actually documented in a place accessible by parents -- no proof, no laptop. EDIT: They have to sign a piece of paper to say they took the laptop, but some kids try and use our machines in place of being organised and getting their own laptop fixed ("if school has one to loan, why fix my own?")
However the boss frequently bends the rules, giving out laptops with no proof of repair, but telling us off if we attempt to do the same thing for the same student she did it for, or walking up and telling a kid (in front of us) not to worry about a receipt just yet, and getting us to loan a laptop out anyway.
She'll also tell us off if we're not paying 100% attention to the kids at recess, but the very next recess, she'll sit at the front desk and do work, only keeping a quarter of an eye on the kids. Other times, she'll encourage us to finish our coffee in the back work area and watch the kids through the glass window at the back -- hardly 100% attention.
All in all, there's a few times a week where this happens (sometimes once or twice a day)
The rules seem to change based on the present situation, who is dealing with the situation and what kind of a mood she is in. If the employee has done nothing to piss her off, they'll get off lightly. Make a mistake, and she'll tell them off in front of other employees, and sometimes the students too. If you're a female employee, you're more likely to get off (she openly admitted to only interviewing one person on our team because she thought he was a female, based on his name)
If we mention these to her, she shrugs off the hypocrisy as her being the boss and being able to bend the rules. Documenting such instances is hard to do, because most of the rules she's changing aren't formal (such as supervising the students. Our contracts state that we're to supervise, but doesn't forbid us from standing at the desk for two minutes, checking an email and keeping half an eye on the two dozen kids in the library)
TL;DR: My boss temporarily changes the rules all the time, even if those changes go against written policy. She'll then tell us off for doing what she does, and then brush us off if we try and bring her up on it. How do I deal with her inconsistency on the rules?