Neat idea, but the dizzy majority need not fear for their immortal souls! An "unfair term" in a contract or other legal agreement is unenforceable - it's one of the reasons why the Office of Fair Trading is investigating the banks and the charges they apply. You might sign a contract with, say a loan shark, that "allowed" the other party to kill you if you didn't comply with their terms - however, if the other party did kill you they'd be breaking the law. If they tried to sue you for the right to kill you, the court would rule against them.
In a consumer society there are inevitably two kinds of slaves: the prisoners of addiction and the prisoners of envy.