Apparently SILENCERS have to be registered. What noble positive innocent reason would a shooter have for using a SILENCER? Ever use one? Y?

Silencers are used for more than one reason.  

1. They protect the shooter's hearing during practice shooting (we do want people to know how to use their weapon)
2. They reduce recoil on the shooters body.  
3. Does not spook the hunting animals so can get a more accurate shot. 
4. In woods near urbans areas helps keep neighbors from entering the woods to see whom is shooting. Keeping the situation safer. 
5. Less noise to disturb the neighbors. I would not buy property next to a shooting range. But some do and then complain about the noise. 
6. If used in the home for defense just one shot could cause permanent damage to the occupants hearing. 


So as you see, 5 of these 6 reason are for improved safety of the shooter and neighbors.