This is a hard decision....it depends on how bad you need to sell your bike. I also would not want to sell my bike to someone 16 year old and have them go out and kill themselves with it....but on the other hand if you are in dire need to sell it, the responsibility would fall on the parents of said 16 year old to make them go to a safety course, blah blah blah. You cannot control the actions of others....BUT if you are NOT hurting too badly and you can afford to pass up on that person...that might keep that person from eventually killing themselves.
Ok NOW...all the 16 year old reading this will probably flame me:lol but I can honestly say that when I was a 16 year old, I was fairly conservative....but shit I STILL loved to speed around and race cars whatever.
Basically, if you can afford to pass up on them it may be in their best interest. Hope this helps :hellobye