It is a fine line to walk! My strategy was to lead them to the conclusion that whole grade acceleration would be the least trouble for them--and truly it is. There was no way that my son's K teacher would have had the time or resources to give him appropriate work. Also, I feel that socially he is better off in a class where he is doing the same thing as everyone else instead of being pulled out or set to work by himself on a separate project.
It is so hard to negotiate with people who could make life very unpleasant for your child. If you have no other options then they have more power over you that way.
