You can't even trust people with good intentions AND knowledge (why do economists miss their predictions SO much?)
And especially you can't trust people when they're not risking their own money. They're just not going to put the same effort, even subconsciously, because... well, it's not their money.
Some people might know; certainly, some few people have managed to do better than chance at investing, or at macroeconomic policy. However, it is not popular knowledge.