I imagine that Hades would make sure there is no opening to the Nevernever.  His inmates are there
for a reason and he hasn't allowed any to escape as far as we know.

All his inmates are ghosts though so I don't think he has to worry about them escaping because they don't really have a body. Its been a while since I read ghost story but I remember Harry casting through Molly and not by himself so I don't think ghosts can open portals and run away. Therer is also the myth of Orpheus so we know living creatures can get out of the underworld, another example of that is Harry himself just getting out through the gate he opened beforehand

So two of the seven laws of magic are:
1) Thou shalt not enthrall another
2) Thou shalt not invade the mind of others
But isn't enthralling a type of mind magic? So the second rule kind of covers that already? Why make a rule about enthralling when you already have a rule against all magic affecting somebody elses mind?
Maybe I missed an explanation somewhere. Anybody has an answer?