Currently if you want the co-captain feature enabled for TeamRaiser, then you have to allow contacts between team members or team captains to be shared.  The co-captain setting should be separate from the contact sharing setting.  Some participants are confused why contacts they didn't add are showing up in their contact list.

This is under TeamRaiser>3. Edit Event Options>Edit Advanced Options>d. Define Misc. Options>1. Current Team Members Visible in Address Book and Team Roster of Participant