In the following cases, the boards found that there was an (implicit) obligation to maintain secrecy:

In T 1085/92 the board took the view that, where contractual relations and development agreements existed, a secrecy agreement could be assumed to exist.

In T 838/97 the board held that an agreement which ruled out availability to the public did not necessarily have to be a contract made in writing, as an implicit or implied agreement could also be taken into account (see e.g. T 818/93).

In T 830/90 (OJ 1994, 713) the board, faced with the facts of the case, took the view that a confidentiality agreement had – at least implicitly – been reached. This was perfectly sufficient. Furthermore, in line with general experience, it had to be assumed that such an agreement would be observed at least as long as there was a common concern for secrecy. Such concern would last at least for the period required to safeguard the interests of the business partners.

In T 201/13 the board concluded that the evidence adduced had been covered by at least an implicit confidentiality clause, based on a thorough examination of email correspondence, the outcome of which had been corroborated by witnesses, and a consideration of the length of the business relationship between the firms involved. However, the (continued) existence of an implicit non-disclosure agreement in the time between the patent's priority date (20 February 2004) and the emails sent in late January 2007 was in keeping with normal business practice. The board could see no conclusive evidence to the contrary.

In T 799/91 the opponents asserted that the subject-matter claimed had been in prior public use in that its manufacture had been "sub-contracted out" to a third company. According to the board the third company was not simply any third party because the opponents' decision to place an order was based on a relationship of trust. The board therefore saw no indication of there having been prior public use, nor could the claim have been substantiated by the testimony of any witness.

In T 2/09 the board took the view that, where a party’s own interest in secrecy could be established, then the situation would be analogous to that of a non-disclosure agreement between the parties involved.

In T 1829/12 it was not in dispute that an explicit non-disclosure agreement had been entered into, but the appellant (opponent) contended that it had been of limited scope and had not covered the sensor unit at issue. The board rejected its contention as being at odds with normal business practice. No convincing reasons had been put forward as to why the sensor unit, of all things, should not have been covered by the explicit non-disclosure agreement.

In T 2170/12, in which the public availability of a project report was in dispute, the opponent had produced a statement by one of the report's authors that there had been no confidentiality obligation restricting the use or dissemination of any project information. The board, however, found that the report appeared to have been circulated only among people working on the project (which, the proprietor maintained, implied its confidentiality). It did not seem to have been sent to a wide circle and there was no specific evidence to support what the author had said in his statement. Considering also the short interval in question (less than four months), the board held that the report's public availability during this time had not been sufficiently proven and ultimately disregarded it as prior art for the purposes of examining inventive step.

In T 833/99, during invitations to tender, the municipal employees had been required to observe confidentiality. The appellant (opponent) said they might have breached that confidentiality, e.g. by informing repair workers of certain steps in the process, but did not back this up with firm facts such as dates, circumstances, etc., or with other evidence. Mere suppositions could not be entertained; they were not proof, and the onus was on the appellant to show that its allegations were well founded. Lastly, the board observed that there was no law to the effect that the confidentiality governing tender procedures ends when they do.

Finally, contrasting with the above, a particular example of the absence of an implied obligation of confidentiality in case T 1798/14 took the form of a witness's visit to a firm's premises. It was in dispute whether he had been subject to an obligation to maintain secrecy, something he had repeatedly denied in his testimony. The respondent (patent proprietor) argued that he might nonetheless have been under such an obligation without knowing it. The board observed that it was not normally possible to furnish positive proof of the non-existence of a fact (here, an obligation). However, the non-existence of an agreement could instead be proven by showing that those who ought to have been informed were unaware of it. The business relationship between the witness and the company in question concerned a technical field that was not related to the said site visit. The board concluded that there had been no tacitly agreed obligation.