i don't think horses become nippy/disrespectful from treats. i think they get that way from having no respect to start with. he was VERY nippy when we got him and a week of no handfeeding cured that. now he gets treats a LOT. and hugs, walks, talking, singing to and worked a lot. i can hold a carrot in front of him and tell him to wait, back up, bow, follow me and back up again. he is very patient and understands it's up to me when he gets it. it's to do with your whole relationship with the horse. you can't pinpoint one action and think it will affect what you do the other 99% of the time.