After having done several transition and non transition starts, I have to say that I am not a fan of transition days. I don't feel it lessens the "trauma" of separation - except perhaps for the parent.
I do of course honour parents' requests if they wish to do transitioning. I charge my half day fee, which is 15 dollars less than my full day fee. The child comes at 11am, stays for lunch and nap, plays for a bit, then goes home.