as far as i can see, if they use any code from the tutorial, or any number of released heros they should release it simply cause the code they used isn't theres and have no right to keep it to themselves...
if they code it from scratch then they have all the rights in the world to it
Currently im working on 3 or 4 heros, all of which i plan to release here, the first ones will be not much more than modified code of stock heros (Asclepius, choob) but as i gain in scripting ability i intend to make them as unique as possible