Quote Originally Posted by Seraph View Post
Actually, there is a gray area, between safe and not safe. There you will find lurking the 'not unsafe'.
Exactly right. "Not unsafe" implies "not inherently dangerous, but possibly there's a risk of danger if one lacks common sense, etc." Like, if a boy wants a skateboard and his mother is against it because she fears he'll break his neck, you could say to her "Skateboarding is not unsafe IF your son wears proper protective gear and goes to a neighborhood skateboard-park instead of riding in the streets."