[Jdanz]

without getting into any details, the main arguement as to why it would be unjust is that it would be usury due to the relative power of bargaining positions.

If you were starving and i offered you some food for all your worldly possessions it would be a fair deal, but there are those who would say that although voluntery it's unjust.

(yes this is incredibly simple and ignores the consequences of pirce controls, but it's the main idea)