I have a rule of thumb these days. Anything crazy that I hear the military, NSA or FBI are doing - I take it as being true, rather than a "conspiracy theory".

I think I have a much higher chance of being right than not, in most cases. So I'd rather think like that by default, especially with many former "crazy conspiracy theories" being confirmed as true by more recent leaks and whistleblowers.

I think most people still think the opposite, though, so even if something big gets uncovered, they won't really believe it to be true "in their hearts".