Nothing ever bad happened when societies trade high trust for low trust. No sir. All roses and sunshine. Certainly worthwhile for me to bend or break any rule keeping me from my best life.
FWIW, I don't advocate blind trust.
Perhaps you meant to say we should teach the reality that cheating exists and is bad; not to pretend it doesn't exist? Or that it's hopeless to be honest and trustworthy because some others may not be? Which leads to ... apathy or more cheating and less trust.