1) I would think it's outlawed everywhere? Someone can correct me if I'm wrong though...but its destructive nature would make it unwelcome just about everywhere.
2) http://ffxiv-roleplayers.com/showthread....#pid133888 [best answer as to why that I've seen]
3) Don't use their magic in public would probably suffice...
4) It's important that your Black Mage have a soulstone. Those who don't will spontaneously combust...Black Magic isn't really void related, so you don't have to be all "Imma summon demons and shit."
...
I think that thread I linked is really the best explanation for what it is though...
2) http://ffxiv-roleplayers.com/showthread....#pid133888 [best answer as to why that I've seen]
3) Don't use their magic in public would probably suffice...
4) It's important that your Black Mage have a soulstone. Those who don't will spontaneously combust...Black Magic isn't really void related, so you don't have to be all "Imma summon demons and shit."
...
I think that thread I linked is really the best explanation for what it is though...