It’s a tool to go closer to a more stable inflation target
https://en.wikipedia.org/wiki/Quantitative_easing
Not a magic way to gain more money.
So inflation doesn’t happen if companies don’t realize that they could raise prices and that people could afford it right?
See it’s very complicated but to see how we act money out we can observe that in the end there is no inflation
You’re basically saying, what if markets didn’t function, so yes, a lot of classical economics would be thrown out of the window then.
I mean
The only one who would be pissed that people are getting free money and they don’t know are companies wanting to make money right
The companies also don’t actually set their prices by looking at central bank reports and basically everything in existence that can affect them. Supply and demand just correct each other naturally over time, so it doesn’t matter that noone is told. Just the fact that more money is in circulation matters.
How do companies do it
how would ANYONE know if the government printed a dollar or two every once in a while
Pricesetting is highly complex and varies business to business, so couldn’t really say.
People working inside the gov leak it to their families and the families spread it across social media?
Money is only worth something in relative terms. So just printing more of it doesn’t matter.
If every 1 dollar is suddenly worth 10 dollars, nothing would change.
I probably made like 5 fallacies in my last statements, but meeh I took all my economics classes like 3 years ago. 
What if I had a 100,000 dollars and I time traveled back in time when it was worth a lot more. How would that affect the economy