This is an extreme example of illegality. But you would want to consider whether Walter can enforce the contract with Jesse. Specific performance is obviously unlikely, but could Walter sue for damages? Or for restitution on the basis of total failure of consideration? Can Jesse simply keep the deposit? Of course, both parties have committed the criminal offence of conspiracy, and it may be that you think that neither should be able to go to the courts for relief.
The question of whether the law is satisfactory is the burning issue in the law of illegality at the moment. It requires critical engagement with the decision of the Supreme Court in Patel v Mirza.