T 1713/11 vom 12.12.2012

Admissibility of the interventions (yes)
Oral submissions by accompanying person (allowed)
Feasibility and/or added subject-matter - main request and auxiliary requests 1 to 17 - requirements not fulfilled
Auxiliary request 18 - admissibility (yes) - inventive step (no)
Reimbursement of the appeal fee (no)

1. Intervention is conceived as a procedurally exceptional situation which is justified only by a substantial legitimate interest of the presumed infringer to enter the opposition proceedings. On deciding admissibility of an intervention it is preferable to concentrate on whether the action of the proprietor reaches the level sufficient to establish a substantive legitimate interest to intervene (reasons 2.2 and 2.6).
2. As long as a patent proprietor or any other party entitled to do so initiates proceedings meant to establish whether a third party is commercially active in an area that falls within the patent proprietors right to exclude, such proceedings are "proceedings for infringement" in the sense of Article 105.