Not to open a whole new can of worms but this might not be a copyright issue per se but a licensing issue. However I seem to remember that the courts have held that license restrictions that are not readily visible before the item is purchased are not enforceable. I seem to remember that software companies tried to claim restrictions that were not spelled out before the purchaser bought the item and lost their cases. Not a lawyer but should think this would follow the same logic. However, as Ghostrider said, they have the money to make trouble so you may not want to get into the hassle and expense.