As for the exemptions of certain groups of people goes.. the exemption would allow you to buy/sell prohibited items but you would still need to put your name in the registry.. those not on the exemption list would be on the registry and not be able to buy any additional exempted items.
Exemption or not you are still subject to putting your name on a list. I will not put my name on a list. A list only leads to future discrimination or confiscation. It opens you to danger whether it be a public/business/social black list or a way for a random person to Dox or Swat you.