not a lawyer but there are some things a contract can't do no matter how signed, dated, and notarized. I think things like liability waivers for theme parks is an example. If a theme park roller coaster kills 50 people the signed liability waivers aren't a get of consequence free card for the theme park.

Yes. You're right. I meant those as hypothetical questions to the person saying "they signed a contract". That excuse has been used to excuse a lot. I hoped that thinking about what is and insert excitable because of a contract might change some minds.

Legally speaking it is as you say, but I was asking from a moral perspective.

Of course, there are plenty.

But repaying training fees aren't one of them unless they don't make sense.

If you're a cashier and after 2 hours know how to do your job, your employer can't write a contract that says "Training costs $500,000 and you must repay if you quit before 5 years".

Contracts law is well developed and you can't sign a contract where you don't receive consideration. And I assume if such consideration is small, but the obligation is huge, the courts won't enforce it.