Most of the Relationship Values for Tifa/Aerith date sequence in the original game makes sense. But in Crisis Core, it really bugs me that the way to increase Aerith's affection with Zack is to be a schmuck continuously. You have to believe in all the market NPCs while they help you, when they are obviously treating you like an idiot and letting the thief run away. So... what exactly does this say about Aerith — she likes her men naive to the point of being a Cloud Cuckoo Lander?
I interpreted it as "points for being in-character", since Crisis Core's date points differ from FF7's in that the only possible outcome is Aeris, and, to be fair, Zack is pretty much a grade-A sucker. I mean—look at how suggestible he is when interacting with, say, the other 1st Class SOLDIERs, or with Yuffie, or even with freaking Hojo, who, if you inspect the giant sample tube while you're protecting him, manages to trap Zack inside just by telling him to look closer for what's in it (nothing, until Zack himself).
I think she's just into schmucks. Corneo's mansion, anyone?