I suspect that tit for tat works better than grim trigger in the noisy environment of social interaction between humans. Your strategy also raises the question of how you tell lies and errors apart.

Personally I never (fully) trust anyone, but still try to treat everyone friedlily (meaning that I'll help them if it costs me little, but I won't nesessarily spend resources on them). Additionally, to protect my own trustworhiness from lies and errors of others, I try not to forward information without also telling the source (not "X is Y", but "I heard from Z that X is Y").