In T 739/92 an oral description of the invention had been given in a conference. The question was whether the participants at this conference were bound to secrecy and could therefore not be seen as constituting "the public" within the meaning of Art. 54(2) EPC 1973. The list of participants showed that the conference was open to every specialist active in the relevant field. The participants were not prohibited from disseminating oral information from the conference, or from publishing information from it provided that they omitted any reference to the conference. Recording the lectures on tape, etc. and photographing slide material were prohibited. The board held that under these conditions the participants at this conference were to be regarded as normal members of the public since there was no secrecy agreement. In contrast to the situation in T 300/86, the participants were neither licensees of the organisers nor subject to a blanket contractual prohibition from communicating the information they obtained to third parties.
In T 838/97 the invention was presented orally at a conference attended by about 100 of the most renowned experts in the respective technical field including potential rivals. The participants were explicitly instructed that information presented at the conference was not to be used without the specific authorisation of the individual who made the contribution. The board considered that the participants were bound by a confidentiality agreement and thus the invention was not to be considered to form part of the state of the art.