Its like eating a grape at the grocery store. No one is gonna throw you in jail over it, but if every single person that comes in the store eats a couple grapes, the stores gonna notice somethings off. Or just like someone stealing your lunch out of the refridgerator at work. I doubt you could prosecute someone over this, but if that isn't stealing, well i guess i don't know what stealing is. (two food references, i must be hungry)
Look, my wife and kids use my InLaws Netflix. But if Netflix decides to start charging extra for password sharing, I am not gonna act like Netflix is the devil because of it. They could easily only allow an account to work on only one IP address at a time, making everyone who is piggy back riding off anothers account to either be without or get their own account. I think charging extra for password sharing is better than that scenario.