This is simply not true. Once literate it often takes a minimal amount of effort — back of the envelope calculation or google search— to do a first pass test of the veracity of a source.

You're still relying on another party when you do a Google search, hell if you want to get crazy about it, you are relying that you were correctly taught literacy and that when you read a word, the meaning it has for you is the same meaning the author attributed to that word. It's not guaranteed