I'm not saying that people who don't work out should not be let go, and I'm certainly not saying that you "owe" people anything. It's a business and not a charity. (Just remember that this goes the other way as well; people who show loyalty to some company are doing themselves a great disservice, in my opinion. I work for money. I'm passionate and will do great work, but I'm a mercenary.)
That being said, I would be very hesitant to go work at a place known to err on the side of just hiring someone and kicking them to the curb if it doesn't work out. Why? Because it can say a great deal about the management at that company, and how they will treat me. I also have no interest in being hired unless you are confident that I'm a great fit. I don't want anyone to take a chance on me. I want people to be delighted to hire me over someone else.