That's how the folk get you

You gonna get trapped by them faeries you keep messing around like that. They don't play by our rules and it doesn't matter what you say. The receiver decides whether the obligation exists and faeries don't mess around with that stuff. For that matter, some of them will decide you are now obligated to give them a favor because they accepted your cookies. The acceptance was their favor to you and if you're fool enough to go around placing yourself in their debt then they'll happily take you up on it.