This question is impossible to answer directly, primarily because we have no idea what they're claiming in their patent application.
First off, keep in mind it only says patent pending. Strategically, the ability to use that term can have at least some inherent value of its own (e.g. attracting potential investors or discouraging potential competitors). Anyone with a few hundred bucks can file a provisional patent application on anything they want and label it "Patent Pending" for a year. For a couple of thousand more they can file a non-provisional and it will still be a year and a half before their application gets published. That's two and a half years of having "patent pending" on your website without having to explain to anyone outside the patent office what it is you're actually claiming to have invented. (Assuming you can stave off a final rejection - depending on how lame your application is and how motivated the examiner is that could be anywhere from trivial to impossible/expensive.)
Of course, that's just the extreme corner case of getting the best return on investment one can get out of the system without actually intending to obtain a patent. There's no reason to assume that is what Lockitron is doing.
They could have filed claims aimed at protecting the broad concept, and frankly it seems like they certainly should have - as I mentioned in another post, the best strategy for an applicant is frequently to ask for the broadest claim coverage you can support with your specification and let the examiner tell you where the prior art is hedging you in.
But even beyond the broad idea you think is "pretty damn obvious," they could be going for something narrower, e.g. something innovative they had to do in order to solve problems raised by their particular implementation of the idea.
Just as a possible example, their website mentions "intelligent power management" - maybe they came up with a novel and non-obvious way of conserving battery power while still being reliable. Speaking of which, what happens when a Lockitron runs out of juice? Are users locked out or can anyone let themselves in? Solving that issue could generate some patentable ideas. What about security? Maybe they've came up with features to prevent someone stealing your lock/unlock credentials off the airwaves. The customizable-shared access feature the website talks about would probably be worth filing on too.
That's just what I can pull out off the top of my head from looking at their website. I am not saying any of that is ultimately patentable, but there's plenty of room to try.