I'm sorry, but that's like saying refund policies in stores has the potential to create thieves. In my very personal opinion that is something I as a customer would find extremely offensive. To be very blunt here, and before I am keep in mind I myself am a digital content creator; my game might be in development still, but I run a one-man company on the side producing digital graphic design and systems development. My stuff has been stolen before. So I do not say the following lightly, but I think it needs to be said.
For the longest time people creating digital goods have wanted the same benefits of protection and prosecution of "thieves" as that of retailers of physical goods. That is to say, a copy of a digital product should be prosecutable just like theft of a physical product in a store where nobody gets physically hurt in the process, as that would obviously be another added crime. This is the reality that is also happening, slowly: downloading illegal software, music, videos and other goods is prosecutable and also prosecuted in more and more countries. Laws are getting in place for it. One of the drawbacks for retailers of physical products is the fact that refund policies are there to protect the consumer, and almost all physical retail stores must abide by this. Now this has come to the realm of digital goods. It's not there because of the ability to prosecute digital "theft", of course, but it is a result of an environment that is making it harder and harder for consumers to make informed decisions when purchasing digital content, and the drawback of buying digital is that you can't go back to a physical store and argue with the clerk: you have to rely on contact forms and help desks that might be unreachable for weeks, effectively locking your money off from you until they decide to answer your request.
There's risk involved in buying digital content, just as there's risk involved in selling it. It's exactly the same as physical retail in that regard. The benefit we as digital content providers have is that when someone steals one of our products, we don't lose the costs of the materials, packaging, transport and other involved costs in producing physical goods. However our goods can then be copied again and again, which is the drawback compared to physical.
There's risks for both customers and creators. Let's not treat our potential customers as thieves just because they could be. You cannot do any business transaction without a degree of trust and even without Steam's policy, what's stopping me from zipping all my DLC packs and sending them to a friend? Nothing except you trusting me not to, and me having the morals to not do it. And the fact that if found out, I might get in trouble. Steam's new policies won't change this one iota.