In G 4/92 (OJ 1994, 149), which relates to inter partes proceedings only, the Enlarged Board of Appeal held that, in view of the right to present comments, a decision against a party who had been duly summoned but who failed to appear at oral proceedings could not be based on facts put forward for the first time during those oral proceedings. Evidence put forward for the first time during oral proceedings could not be considered unless it had been previously notified and it merely supported the assertions of the party which had submitted it. However, new arguments could - in principle - be used in the reasons for the decision as they did not constitute new grounds or evidence, but were reasons based on the facts and evidence already put forward.
According to Art. 15(3) RPBA (Art. 11(3) RPBA 2003), "the Board shall not be obliged to delay any step in the proceedings, including its decision, by reason only of the absence at the oral proceedings of any party duly summoned who may then be treated as relying on its written case." The preparatory documents to this Article state that this provision does not contradict the principle of the right to be heard pursuant to Art. 113(1) EPC since that Article only affords the opportunity to be heard and, by absenting itself from the oral proceedings, a party gives up that opportunity (CA/133/02 dated 12 November 2002). This RPBA provision superseded the findings of G 4/92 with regard to the non-attendance at the oral proceedings before the boards (T 706/00). To the extent that G 4/92 deals with the general admissibility of new arguments in appeal proceedings, it was also modified by the amendments to the RPBA introduced with effect from 1 May 2003 (T 1621/09). G 4/92 still applies for the departments of first instance (see Guidelines E-II, 18.104.22.168 – June 2012 version). With regard to proceedings before the examining divisions, see also the notice published in OJ 2008, 471.