On: The FBI, CIA and NSA say American citizens shouldn...

[twmb]

Intelligence agencies generally avoid saying exactly why they suggest something and how they came to that conclusion. If agencies were fully open, adversaries would know what holes _they_ need to plug.

[TheSpiceIsLife → twmb]

I'd go one step further and say that intelligence agencies rarely say what they mean. It would be naive to take any of their statements at face value.