It is a very sticky situation, and all boards have to be so cautious with what they say for fear of a big liability. We have to keep a very close eye on someone really digging into any particular place on our board too. It's too bad you have to tiptoe around some of the reviews, but it's become a way of internet life.
It almost always turns out to be the board owners who will be liable if someone takes offense to something someone has said.
The thing I don't get is how places like E-pinions actually thrive on just such reviews (good or bad) without any worries.