Due to their aesthetic preferences, the Dragon Tribe often returned princesses they had abducted. What would be the point of keeping them? They didn't fit the dragons' standards of beauty, and as food, they hardly provided enough nutrition. As intelligent creatures, they surely had to consider some issues when choosing what to eat, right?
Issues like whether the food was clean, for instance. Swallowing raw flesh is one thing, but to think about what the other party had also consumed... tsk tsk, if their peers found out, they couldn't defend against insults of having ingested such things.
Thus, after the games of heroes battling evil dragons that the demigod dragons concocted were over, the princesses and such were generally 'rescued'. For the abducted princesses, this actually resulted in a sufficient boost to their reputation. After all, they were princesses who had survived a dragon ordeal, which made them somewhat more special than just any ordinary princess, didn't it?
