It actually only affects the Pterois family of lionfish, and only in Florida, effective August 1,2014. Granted those are the most popular in the aquarium trade. The ban does not restrict current owners in the state, however the fish cannot be carried across the state line by hobbies.
You can harvest all you want in Florida waters, however, Im not sure if they are allowed to sell them live to hobbyists.
The current issue of Coral Magazine is nearly dedicated to this issue.