1. if you get the “answer my call” text, NEVER ANSWER THE CALL. 

They are calling you because they want to have the conversation verbally, and be able to lie later about what they said or didn’t say. Force them to continue via text or email- force them to continue the conversation in writing or not at all. 

2. “Lack of 2 weeks notice is unprofessional!” or the other version, “Not providing notice is illegal!”

No it isn’t. Neither is true. 

And in the US, all states except Montana are “at will” employment (though you may hear an employer refer to it as “right to work” to make it sound better, it’s the same thing). Sure, at-will employment means they can fire you without cause, BUT! It also means that you are not legally required to give a reason for quitting, or to give notice of any kind. 

Is it polite to give notice when you can? Sure. Do bosses expect it? Absolutely. But that does not make you legally required to provide it. 

3. The only thing I would change in the worker’s interaction here was their response when initially asked to come in. 

Employee: “Hey Mark. Sorry I’m unable to cover the shift tonight because I’m studying for my exam tomorrow.” 

Don’t give a reason for your lack of availability. It may be tempting to. You may feel rude if you don’t. 

DON’T DO IT.

You do not owe your boss any information about what you do off the clock, and any reason you give will only ever be used against you. 

Boss: “Hey I need you to cover Jasper’s shift tonight.”

Employee: “Sorry, I’m not available.”

And leave it at that. 

Do not elaborate. 

Do not offer additional information. 

When you boss asks you to elaborate, because they will, be polite but firm. “With respect, that’s personal. I’m sorry, but I’m unavailable to cover this shift/work late/come in early/etc.”

Be a broken record- you’re unavailable. That’s the only information they need to know, and it’s the only information they have a LEGAL RIGHT to know.