The "loophole" requires the seller to verify the buyer is a Florida resident of legal age.  Also if there's any indication the buyer may be a prohibited person, the sale cannot happen.  I personally would only sell to someone who is a Florida resident with a valid Florida CWL, but I don't ever expect to have that problem since my few old relics are not for sale. 

 

As for keeping criminals from getting guns, that's difficult since they don't seem to follow laws.  But even if guns didn't exist, criminal violence would be a problem.  A knife, piece of pipe or a ball-peen hammer can be just as deadly as a handgun and much simpler to operate.  The best tool for self defense is not an object or weapon but a comprehensive mindset.  Develop situational awareness.  Don't go to stupid places with stupid people to do stupid things.  Nothing good happens after midnight.  Adhere to these few basic tenets and your chances of being attacked are greatly reduced.

---