But that only works if enough people can be counted on to follow the norm. If too many people are following the deviant strategy, then the level of mistrust rises, and it's not a successful strategy any more.
Reminds me of Jon Snow in the last Game of Thrones:
I'm not going to swear an oath I can't uphold. When enough people make false promises, words stop meaning anything. Then there are no more answers, only better and better lies.