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

A product made available for test purposes is to be treated as confidential. Sale of the product in a limited quantity is regarded as sale for test purposes, if the product is normally sold in large quantities (see T 221/91, T 267/91 and T 782/92). In T 221/91, the board held that it was for the patent proprietors to prove the existence of an obligation to maintain secrecy when the opponents had proved that the invention had been made available to the public and the patent proprietors had claimed the existence of a secrecy agreement (see also T 1407/09).

In T 37/98 a limited quantity of tape laminates had been delivered to three customers of the appellant. The delivered material had been used exclusively for test purposes, even after the priority date of the patent in suit. This was confirmed by the fact that such a laminate was usually delivered in large quantities. The board concluded that the delivered material had to be treated as confidential. In a case where only test specimens were sent to a customer, it had to be assumed in principle that at least an inherent secrecy agreement existed. If this should exceptionally not be true, the exception from the usual practice had to be proved. The mere statement that there was no secrecy agreement, as made in the present case, was not sufficient for this purpose.

According to the board in T 1847/12, the relationship between a firm and another that it contracted to develop and deliver prototypes could not be treated as equivalent to that between a dealer and a customer. General experience showed that a vehicle became publicly available when the manufacturer delivered it to a dealer, because then anyone could buy it. But the same did not go for a delivery under a development contract. The development itself takes place in a confidential way. The board on this occasion made some observations on the status of third party. The board found that the written statement made by an employee of the contractor (Schrick GmbH) that, "as far as [he] knew", the prototypes had been delivered to the client (Opel) without any duty to maintain confidentiality was irrelevant because it was the client placing a contract, not the contractor, that decided whether confidentiality applied, i.e. here it had been for Opel, as client, not Schrick, as contractor, to decide whether the prototypes' development was to be treated as secret.

There was no obligation to maintain secrecy in the following cases:

In T 7/07 a third party had claimed inter alia that the main claims of the patent lacked novelty over a prior use, namely, the conduct of clinical trials with contraceptives containing the composition claimed in the patent. The participants had been informed of the ingredients but had not signed a confidentiality agreement, and not all unused drugs had been returned. The board came to the conclusion that the handing out of the drugs to the participants rendered them publicly available and that it was possible for the skilled person to discover the composition or the internal structure of the product used in the clinical trials and to reproduce it without undue burden.

In T 945/09 the teaching according to claim 1 of the patent in suit was used by a patient while having "home parenteral nutrition" (HPN). The opposition division had concluded that all information concerning the use of taurolidine as a catheter lock available to the acting medical team, to the patent proprietor (supplier of taurolidine) and to the patient, was covered by an implicit obligation of confidentiality which stemmed from the specific circumstances of the case. The board held that there was no reason for the patient to treat that knowledge as a secret, because at that time the acting doctors simply tried to apply taurolidine of whatever provenance using a technique they derived freely and easily from the state of the art common to them at that time.

In T 602/91, in the board's view, there had been no tacit agreement, as the two parties had not concluded a development agreement or entered into any other contractual relations that would indicate either of them having had any particular interest in a secrecy agreement. Furthermore, a single case of co-operation between a manufacturer and a potential end-user of the product was not sufficient to assume that a tacit confidentiality agreement had been entered into.

In case T 809/95 the granted patent was, inter alia, for a plastic bottle, the special features of which related to its foldability. The prior use alleged by the opponents had occurred in connection with a "market test" performed by a market research company on behalf of the third party to gauge the market for such bottles. The patent proprietor claimed that both prior uses had been subject to confidentiality rules. The board held that the very fact that the third party had chosen a test variant allowing the test participants to take the bottles home indicated that it attached no particular value to confidentiality in the patent sense. Nor was there any circumstantial obligation to maintain secrecy since the market research institute did not employ or have a business relationship with the test persons.

In T 1464/05 the board considered that the mere fact that a product has been delivered possibly for carrying out tests in what appears to be the result of an ordinary commercial transaction does not constitute by itself, in the absence of any other special circumstance or supporting evidence, a sufficient condition for concluding that the product was necessarily delivered under an implicit confidentiality agreement (see in this respect decisions T 602/91, T 264/99, T 913/01, T 407/03, and T 1510/06). There was no indication that any express secrecy agreement existed between the two companies, but also no indication that any particular or special relationship existed between the two companies other than the ordinary relationship between a seller and a buyer company. As held in decision T 681/01, "there must be something in the circumstances that suggests that a confidential relation existed before a delivery which appears to be the result of an ordinary commercial transaction can be disregarded as not making the delivered goods available to a member of the public".

In T 1054/92 of 20 June 1996 date: 1996-06-20 the opponent had alleged and proved that the claimed invention, an absorbent structure for diapers, had been tested in public tests carried out by several hundred members of the public at several places in the USA over several weeks. The board was convinced in the light of common experience that it was very unlikely that these tests had been kept confidential, particularly since some of the used diapers had not been returned to the appellant.

In T 2068/15 the board accepted that that, if joint development projects are agreed, they often are – explicitly or implicitly – combined with an obligation of confidentiality. In the case at hand, the board did however not see enough indications from which it could be convincingly concluded that a joint development project existed. The circumstances were suggestive of ordinary sales rather than the sending of samples in the framework of a joint development project.