I’ve seen characters that look like they are controlled by bots, yes. The fact of the matter is the player can rarely know for sure if someone is botting.
Blizzard states here:
Since I’m assuming you don’t have access to the same sort of technology, there’s no way for you to conclusively know if someone is botting or not.
Moreover, Blizzard also states:
So it is entirely possible that what you are seeing is player controlled and not botting. You can still report them by all means, but uploading an expose video and declaring with 100% certainty that they are bots might be jumping the gun.