Using a VPN to bypass such a restriction is just as much a copyright violation as downloading from thepiratebay.
Either way you are creating an unlicensed copy, or at least a performance, of the work. It would be the local license holders right to go after you, or Netflix, for violating "their" copyrights.
The copy is licensed since it's made available by the distributor to the customer. It's the distributors duty to the determine if a customer is eligible for purchase or not, best way would be having to provide a verifiable invoice address within the region of the granted license. An IP is a best guess at best, but not a verifiable proof of the physical location of the end customer. Netflix doesn't ask for an invoice address, Amazon Prime does. Amazon also has siloed accounts for each market where you would have to have multiple subscriptions in different countries to access the local offerings, where as NETFLIX has only one global platform. If an US-resident purchases a US-NETFLIX subscription travels abroad for a short or long period it shouldn't make a legal difference if a private VPN to the home's IP or a commercial VPN service is used.
By all enforceable concepts the place of purchase of the subscription is the relevant thing for having a valid license for private use, not the place of consumption.
Also I can't see why the first-sale doctrine wouldn't apply here either. Rights holder sold a distribution license to Netflix under certain restrictions (first sale). With Netflix distributing the copy to the end customer. http://en.wikipedia.org/wiki/First-sale_doctrine
The problem with Netflix really starts long before the consumer. With something like Black Books, which predates the netflix concept, nobody has universal distribution rights. The original creator, the BBC, long ago sold the American rights to someone else (PBS?). So there is nobody from which Netflix can purchase worldwide rights. Netflix instead purchases whatever rights they find and must mirrors them. Netflix very recently spoke out on this issue.
http://www.cbc.ca/news/business/netflix-upholds-geoblocking-...
The purchase of a DVD grants you the license to play the stored content for unlimited private screenings from the medium provided. It's both a license and a copy. The first sale doctrine overrides the "For Home Use Only." clause (which is a part of a license) still present on many DVDs and allows libraries and retailers (notably old netflix) to rent out the medium.
BTW, not that it helps you...but Black Books is currently on UK Netflix. http://www.netflix.com/WiMovie/70157495?trkid=13462100