It doesn't matter, because in sane countries, even when such clauses aren't outright illegal, you still have the right to refuse the change and cancel the contract without penalty. I am not sure exactly which countries are sane.
There's all kinds of law about what you can and can't put in a contract. You can't just write whatever you want and then hold people to it. Why do you think they always have a clause that says that if part of the contract is found to be invalid, the rest still applies?
There's all kinds of law about what you can and can't put in a contract. You can't just write whatever you want and then hold people to it. Why do you think they always have a clause that says that if part of the contract is found to be invalid, the rest still applies?