Current many to many group connection codes that are being shared by the call manager can potentially be one of the sources of fake already know connections.
As @monomesa suggested here one solution can be implementing a many to many group connection qr codes for just met level to be used by call managers, so users do not be asked about confidence level and all level be automatically be set to just met.
Another solution can be implementing a one to many QR connection which call managers share and connect to all attendees to themselves using that code, instead of asking everyone in the party to connect to everyone else. I think asking everyone to connect to others in the party with just met level is not helpful and make things hard for users that are trying to connect to the manager to get verified.