It can result in a squelch until a GM looks at it. 99.999% of the people claiming they did nothing wrong and were just mass reported find out there were almost no reports, and that the account action came from only a few - backed by chat logs showing infractions. If chat logs don’t show infractions, nothing happens when someone reports you.
Example from the other day.
A false positive? Yes, those can happen. They do have software that they program to detect known botting software and exploits. It is rare, but there can be mistakes in that. I would not call that an auto ban though really. It is very very intentionally programmed to catch known cheating methods. They verify that the account was flagged before banning it. Now, if the detection criteria was wrong - that causes a false positive. They reverse it and apologize.
Chat bans and cheating bans are two different teams and processes though.
EDIT so the GM email does not say anything about an “auto ban service”. Please don’t make things up.