I think you already put your finger on it--a "good instructor" is the pivot point.
I have little sympathy for those that don't read their contracts as well.
Buts its one thing not "read the fine print" and quite something else to be delbrately misled.
A "good" teacher does not do that--but a "bad" one will.
A good contract should protect both parties---if say my phone service claimed that I can get coverage in "X" region and I can't--then its in breach and I'm out of it.
Most martial arts contracts don't so much as mention "instucture suck-age" in the wording.
A proper contract is NOT supposed to be a clever means of taking advantage of someone's ignorance.
I have NO problem with fully functioning adults having to take responsibility for their actions---which IMO should INCLUDE poor teachers and "scam-a-rei."
Fast-talking some poor sap into signing a punative and predatory contract is IMO something that one needs to be held responsible for.
But I do agree that signing a contract just to get a lower payment then deciding to quite--essentially taking advantage of the teacher--is also something you might need to take your lumps over.