At one point with mine, she was grabbing the bumper without command to beat the pinch, and it wasn't retrieving desire. It was her thinking she wanted to get the bumper before I could say anything or pinch. The word 'fetch' didn't mean anything at all. The only thing that meant something to her was having a hand on the collar, and that meant grab the bumper. Maybe yours is doing the same thing, or will be doing the same thing.
This is just another idea but if she is just lunging everywhere for the bumper, enforce the sit until you descide to give the command. Wait a while after you sit the bumper on the table before you say 'fetch'. That ties the act into the command instead of the situation, and may even get a refusal. At one point or nother freebies have to be done to broaden the lesson.
I would really guess that at the point you are at, your dog is not going solely on retrieving desire. She probally isn't truely forced yet, but I don't think it really matters so much. In the end she will be truely forced especially if you end up using continuous collar force on fetch. I don't know how anyone can say a dog responding well to continuous collar pressure isn't forced. My female looks really forced with collar pressure now.
After my dog was picking up off the ground, I was quickly going into walking fetch, and lets face it in walking fetch you are trying out some freebies for sure. If you dog is picking up off the table I would move it to the ground. I basically followed the progression in the old Lardy Article on force fetch. After picking up off the ground, it says to get the dog moving. Being up on a table slows a dog down a little from what I remember because they are a little concerned about being up high.
If I remember correctly, I was pinching everytime until she was picking up off the ground. Then, I backed up closer to her face for the little refinements or basically any time I thought I needed to do that. Basically, you've got to read the dog and try to do your best.
