NASA made the announcement that they found evidence of water on Mars. Ok.
But why didn't NASA send Mars Rover Curious over to a site with the evidence? It's only about 50km away. Well, the Rover is super slow and 50km is a long way to cover. Perhaps more interesting is:
The site where the water was found is off-limits to Curiosity. Why? Because Curiosity may still be carrying some bacterial spores from Earth, and the last thing NASA wants to do is seed Mars with Earth bacteria.
Yeah, NASA, man. You are dealing with buncha bumbling bureaucratic idiots, you know :)