no thats a fair question
all i can tell you is that the diff can wind up, in other words the viscous fluid its filled with tends to overheat and solidify which renders the diff fooked.
dan will give you a more technical answer than this as im not that up on diffs and boxes, but i do know theres a lot of front diffs out there that do not work as they should and people dont even know it, whether freewheeling for too long a distance causes this or not i do not know
guess its the same with an auto box because if you tow that in neutral it boogers up the torque convertor so suppose the viscous diff works in a similar sort of way