in game-theoretical terms, it's like when someone makes me an excessively small offer in the Ultimatum game, my System 1 infers that they're not an agent and decides that I might just as well do the CDTical thing and accept the offer anyway.

In the iterated Prisoner's Dilemma, ‘assume your opponent is a fellow superrational agent until proven otherwise’ yields tit-for-tat...

Now that you mention it, I've only ever used this tactic on people I didn't know very well, so I expected their resent-o-meter to be average. And then I could use their reaction to gauge their actual resentment-setting. Meanwhile, I have a friend with a resent-o-meter that's perhaps higher than necessary, and I always go with the "Well you CAN'T just hate people for something like that ..." which led to really long, tedious debates about why she shouldn't demonize some gentleman or another. But I think she finds reasons to resent people because it's the only way she knows to deal with sad things. :(