> A high trust society reduces the incidence of scams/becoming victims to scams by reducing the number of scammers and increasing the number of honest people and honest behavior.
Considering that the scammers in this instance haven't been identified, there's a good possibility that the phone scammers belong to an out-group (e.g. infamous Indian/Nigerian scammers) of the victim's society. In fact, it seems to me that trusting more (because the in-group are honest) without appropriate safeguards preventing out-group members from impersonating in-group members exacerbates the problem. So I do not really see the connection between your solution and the problem.
Considering that the scammers in this instance haven't been identified, there's a good possibility that the phone scammers belong to an out-group (e.g. infamous Indian/Nigerian scammers) of the victim's society. In fact, it seems to me that trusting more (because the in-group are honest) without appropriate safeguards preventing out-group members from impersonating in-group members exacerbates the problem. So I do not really see the connection between your solution and the problem.