Indeed, "section 12 requires the party in possession of the knowledge to remove the mistakes in which the other party is involved" (Civil Appeal 578/88 Tefahot Mortgage Bank of Israel in Tax Appeal v. Netzer, IsrSC 34(3) 828, 835 (1989)). It has long been held that, "A breach of the duty to act in an acceptable manner and in good faith can take the form of omission or non-disclosure of facts, when according to the circumstances it would have been reasonable to expect the person, who is conducting the negotiations, to disclose them to the other party. The disclosure required by clause 12 is not necessarily disclosure as a result of the other party's questions, but rather there are circumstances in which it is necessary to provide proactive details of information, which is essential for those who are in negotiations prior to concluding a contract. [...] Proper etiquette is not just silence and refraining from lying... Rather, they are the same honesty and fairness, which in given circumstances require action to be taken in a place where "the wicked would sit and remain silent." [...] There are circumstances in which the parties are obligated to take an active action of discovery ... and especially when it is clear to the owner of the information between the negotiators that there is a real gap between the intention of the other party and what is truly achievable according to the legal and factual situation" (Additional Hearing 7/81 Fender, Open and Building Investment Company in Tax Appeal v. Castro, IsrSC 37(4) 673, 697-698 (1983).
The application of these criteria to our case will therefore necessitate, inter alia, the question of whether there were information gaps or power gaps between any of the defendants and the various plaintiffs prior to the signing of the contracts, and in the process whether the defendants had knowledge and access to data that exceeded those of the plaintiffs. It will also examine whether the defendants, or some of them, breached their duty to act in good faith, whether by making partial representations that do not correspond to reality or by way of not disclosing facts, when according to the circumstances it was necessary to expect them to be disclosed to the plaintiffs.