Kernrechtsfrage
Whether a third party that does not join the defendant after notice of the dispute may still intervene on the plaintiff's side.
Extrahierter Entscheid
Yes. Refusing to join the notifying defendant does not in itself bar side intervention for the opposing party.
Extrahierte Begründung
Section 46 ZPO only governs the rights of the notified party when it wants to support the notifier. It is not exhaustive and does not prevent intervention for the opponent if the requirements of sections 41 ff. ZPO are met.