The Art of Natural Dressage

Yesterday something I thought of strange occured. I was calling the horses to come out of the big pasture and instead of first calling Imperia, I first called Evita and Atreyu. I saw also Imperia running towards the stable (she was in another pasture) and she stopped about 10 m. before the gate. Only when I went to the gate she came galopping towards me and stopped by my side. The first thing wich came to mind was that I gave her a treat a while ago when I stood by the gate and she came and never did this when she was already in the paddock. So it was like she was waiting for me to stand on the "possible treat" spot to come gallopping towards me.

This made me wonder, how do treats effect the way your horse acts outside of training? Maybe only give treats within training or is there no harm in the way your horse interacts during the day? I haven't figured this one out in the case of Imperia and am curious about your opinions and experiences!