Historically speaking, bans have never served much purpose except to demonize certain segments of the population. If a politician wishes to marginalize the opinion of a group of people, just ban whatever they stand for and spread the word that they are risking the safety of everyone else.
Christianity was banned, yet the religion survived Rome's attempts to purge it and finally ended up switching to it. Women having rights of any sort has been banned virtually everywhere at some point yet that never stopped women from having opinions
and now many are heads of state.
They ban alcohol because it corrupts the soul and makes people into monsters. Didn't stop small time crooks from bringing it in from other sources and becoming crime bosses and true monsters.
They ban drugs, still found just about everywhere. They banned gun possession by criminals and the insane, yet insane criminals still cause catastrophic harm with them. They ban smoking virtually anywhere yet people still smoke.
Bans never solve any problem or stop the problems from occurring. Their only real purposes are for politicians to marginalize people they don't like and to provide an excuse for those unwilling to tackle the underlying issues.
The only ban that might be worthwhile in my opinion is one cribbed from Shakespeare when he proposes a solution to the problems with lawyers.
to Dr. Phillips 
