Ryanair seem to be on very dodgy legal ground here, particularly because they are redefining the nature of a contract.
When you make a contract it is assumed that the other party to that contract will act in good faith and not deliberately do something which is to your disadvantage. When you hire a car you do not expect it to be without fuel despite the fact that this may not be mentioned in the documentation.
In this case Ryanair appear to be acting in bad faith and deliberately disadvantaging customers. I would expect some form of legal response fairly quickly.