Whie you are only selling the patterns, you shouldn't be liable for the finished product, in my mind, it would be good if you knew and designed your patterns to enable the finished product to pass safety laws. For example there is a no drawstring law in hoods and waistbands of outerwear, so if you were designing a sweater with a hood, you shouldn't design it with a drawstring. If you are in Austrailia, you should follow Austrailia's children's safety laws. They are much like the USA.'s.