1,451. Appointing an Agent for Kiddushin
Hilchos Ishus 3:15
Appointing an agent to accept kiddushin must be done in front of two witnesses but appointing an agent to give a woman kiddushin need not be done in front of witnesses. The only purpose witnesses would serve in the latter case is to publicize the matter. Therefore, if the agent and the one appointing him both recognize his appointment, witnesses are unnecessary. This is comparable to an agent who is appointed to deliver a get or to separate tithes. In all these situations, a person’s agent is considered just like the person himself and witnesses are not required.
Hilchos Ishus 3:16
Agents can also serve as witnesses. Therefore, if a man appointed two agents to consecrate a woman for him, which they did, then they serve as both agents and witnesses. Accordingly, there is no need for them to consecrate her in front of other witnesses.