The Attack of the Sting Rays

1) These aren't "sting" rays. They are pelagic rays, most of which actually don`t have any kind of barb at the base of their tails (including the giant manta ray of which someone posted a pic). So actually, unless one of these rammed you, they`re actually incredibly harmless.
2) The story of the woman killed by a jumping ray is actually only partially true. The ray was a either a spotted eagle-ray or a cow-nosed ray and she was never punctured by a barb, but was hit by the ray and hit her head. The blow to her head was what killed her, although the ray was an indirect result of her death.