It seems that if the shares are somehow moved to Bitfunder unless you have > 250 you will be unable to transfer them into direct shares so in Bitfunder they would have to stay (unless you sell them). If they become direct shares owners would then have the option of transferring them to bitfunder through the normal method or leaving them in direct or even auctioning them on the forum. It seems that Burnside converting them to direct shares is the simplest, cleanest method and provides the greatest flexibility for his users. I am sure Burnside is taking all of this into account.