In T 712/94 the board allowed the appellant (opponent) to introduce facts and evidence on alleged prior use at the appeal stage, whilst refusing the respondent's (patentee's) request for apportionment of costs. The patentee had been made aware of the prior-use documents during negotiations conducted well before the first-instance decision was taken; so they had not taken him by surprise when submitted after the failure of those negotiations.

In T 1167/06 the board did not consider it an abuse of procedure that two weeks before the oral proceedings the appellant filed three further auxiliary requests, additional arguments and four short documents, the latter illustrating common general knowledge on issues that had already been discussed. The need to translate the requests and documents and the resultant costs were in the nature of the European procedure with three official languages and affected all parties in equal measure. As the language of the proceedings for the patent was German, the respondent had to expect many submissions to be made in that language. The respondent stated that an additional representative had had to deal with the late filing and travel to the oral proceedings because the representative assigned the case had been on leave at the time in question. In the board's view, however, the representative's absence on leave was not the fault of the other party. Moreover, the respondent (opponent) had been represented by the same two representatives before the opposition division, so the additional representative had not needed much time to familiarise himself with the latest dossier updates.

In T 29/96 a new document which was fairly simple and straightforward in content had been filed together with the statement of grounds of appeal. The board ruled that this was the earliest possible moment that the document could have been submitted. In addition, the introduction of the new document could not be regarded as having given rise to a new opposition; the appellant had not introduced a new item of closest prior art but merely a new secondary information source, in an attempt to fill the gap referred to in the impugned decision so as to improve its position with respect to the assessment of inventive step.

In T 554/01 the applicant submitted a number of documents following the negative decision taken by the opposition division. The board held that the mere fact that certain documents had been submitted at a late stage did not justify a finding that there had been an abuse on the part of the applicant, especially where they had been submitted as a result of a legitimate desire to supplement the line of argument which had been unsuccessful before the department of first instance. Moreover, the respondents had not shown that they had incurred additional costs as a result of the documents' introduction into the proceedings.

In T 1171/97 the board rejected a request for apportionment of costs because it was satisfied that the new documents which had become known to the appellants (opponents) in the course of another search had not been filed in order to obstruct the proceedings, but because they contained aspects which, according to the statement of the opposition division, had not been found in the previously available references.

In T 507/03, as a reaction to the reasons given in the impugned decision, the opponent (appellant) filed a new set of documents in the appeal proceedings. Refusing the request for a different apportionment of costs due to the late filing, the board argued that, according to Art. 108 EPC 1973 and R. 65 EPC 1973 (now R. 101 EPC), a statement of grounds of appeal had to identify the extent to which amendment or cancellation of the decision was requested. This, however, did not forbid a losing opponent from filing new pieces of prior art if it was felt that they could counter the reasons given in the appealed decision. Further, the new documents were all easily understandable and had not caused an unreasonable amount of extra work such as to justify departing from the normal rule that each party meets its own costs pursuant to Art. 104 EPC 1973.

In T 242/04 the board considered that the respondent's late filing was made in response to a communication of the opposition division for making written submissions and took place roughly one month before expiry of the final date accorded in the communication as well as roughly two months before the date for oral proceedings. The circumstances were therefore not such that there was no justification for the late filing or that it could be held that the respondent acted in bad faith. In addition, the appellant who requested an apportionment of costs and, in particular, reimbursement of the travel costs of a technical expert, neither gave any reasons let alone any evidence for the necessity of the technical expert's presence at the hearing before the opposition division, nor provided any evidence that the respective trip was caused only by the said late filing. Therefore, a different apportionment of costs was not regarded as justified.

In T 333/06 the board found that the appellant's maintenance of his request for admission of the fresh ground for opposition – lack of inventive step – and of the new supporting documents, after being notified of the board's preliminary negative opinion, did not constitute abuse, as that opinion was not a final decision. Furthermore, even if the appellant had acknowledged that the new documents were not relevant to novelty, objectively he could not be blamed for having maintained them in the hope that his oral presentation would result in the admission of lack of inventive step as a fresh ground for opposition and hence of the new documents relevant to inventive step. Thus, while this had admittedly made the respondent's preparations for oral proceedings more difficult than they would have been if the appellant had withdrawn the new documents, the procedural conduct on the part of the appellant which had necessitated those preparations was not abusive but one of the appellant's legitimate prerogatives.