The question involves two subquestions:

1. Who should formally ask for consent, that is, send out the email? If we stop adding email into the "Volontärer WMSE", then it is only the person who added the volunteer who knows the email; but as Volontärbank is restricted to a few employees it is likely that the person adding the name into "Volontärer WMSE" don't know if the person is already registered in the volunteer bank, or if they are suitable to add.
2. Who should make sure that consent is actually added to the drive? To follow up to make sure that we have the proper consent? That can obivously only be made by those with access to the Volunteer bank.