I am not a lawyer so, while I have this question, I cannot answer it.
My question is simple: Is Scientology’s Contract for Services a valid, legal and enforceable contract?
Certainly, the Church of Scientology’s stable of expensive lawyers would, and do, insist it is fully enforceable — but is it?
I looked at several legal-advice websites. This one has the following criteria for whether a contract is valid:
Identify an offer, acceptance, and consideration. For a contract to be valid, it must have these three basic elements: a specific offer,  acceptance of the terms of the offer, and consideration, which is the agreed-upon exchange of goods or services. 
– A valid offer must be sufficiently definite. It must be clear, unequivocal, and direct.
– A contract must contain consideration: mutual promises to do something or to refrain from something that a party has a legal right to do. Without this mutual promise, there is no valid consideration and the contract is illusory.
Does the Scientology Contract for Services fulfill these criteria?
To be clear, what “specific offer” is the church offering? What “clear, unequivocal and direct” offer does the Church of Scientology propose?
Very specifically and explicitly the Church of Scientology promises to deliver … absolutely nothing, ever.
Neither the Church nor any other Scientology church or organization makes any claim … that any particular result may be forthcoming from my participation.Church of Scientology Contract for Services
And what “consideration” does the church demand from the Scientologist? In exchange for this explicit “nothing”, the church requires Scientologists give up every single legal right they would have to protect themselves. These rights are extremely valuable.
… I am forever abandoning, surrendering, waiving, and relinquishing my right to sue, or otherwise seek legal recourse with respect to any dispute, claim or controversy against the Church, all other Scientology churches, all other organizations which espouse, present, propagate or practice the Scientology religion, and all persons employed by any such entity both in their personal and any official or representational capacities, regardless of the nature of the dispute, claim or controversy.Church of Scientology Contract for Services
To repeat from the website regarding what makes a contract legal:
A contract must contain consideration: mutual promises to do something or to refrain from something that a party has a legal right to do. Without this mutual promise, there is no valid consideration and the contract is illusory.(Emphasis added)
No competent lawyer would ever allow their client to sign such a one-sided “contract”. But, of course, Scientologists are not allowed to take the contract to a lawyer. Further, no Scientologist is allowed to have their own copy of the contract.
More from the website:
Look at the relative bargaining power between the parties. A contract will be considered “unconscionable” where there is a gross disparity in bargaining power between the parties and the terms of the contract are oppressive.
Certainly, it is obvious that the terms of Scientology’s contract are quite oppressive. The bargaining power of a Scientologist in this situation is nil. The “Contract for Services” is a take-it-or-leave-it proposition. Sign it or get out. “Bargaining”? Don’t be silly. “Take it to my lawyer”? Not allowed. Require the church to promise to do anything? Definitely not.
All in all, it appears to my non-lawyer eyes that Scientology’s Contract for Services is not valid. There is no quid pro quo – something given or received for something else. Quid pro quo is the essence of a contract. Scientology’s contract is completely one-sided – to the vast benefit to the church and the massive detriment to the Scientologist.
Is this legal?