Dera - morally I agre with you.
Have you ever seen a poor (financially speaking) lawyer?
In practice one should always read the contract. If the terms are as stated and they are clear then when you sign for the hire you accept the terms. It might be difficult to convince a court otherwise if the school then take action to recoup the costs of recovery. You might win - you hired a serviceable aircraft and this one is not serviceable - you might even get your costs of hotel / returning home; all very unclear unless specified in the contract.
If you don't like those terms, find another aircraft where the terms are different. If something is not covered, ask before you hire and either get it witnessed or get it in writing.