It's not 'having your door open.' it's standing on the street corner shouting 'free beer! help yourselves and take some for a friend'
In a fully automated way with no precautions to make sure the same guy doesn't stroll by 1000 times.
So maybe a better analogy is the people that push flyers in your hands on the street. Take a flyer! take 10! take 1000!
What? somebody took 1000? You dunce, we have to pay to print those!
The fault lies in the person that trained the bot to push the flyers out, not in the person that willingly took as many flyers as the bot would give it.