Appropriate sources of entropy

> Why is it just a possibility? I don't get it -- what could possibly be said against that?

I think they mean a possibility in terms of "it's possible to write code that isn't too ugly",
rather than "possible" in the theoretical sense. Of course, the worst it can do is not
increase the entropy. To actually decrease the entropy, if would need to be correlated to some
other information in pool and cause really weird interactions (highly unlikely IMO).