Same over here in Germany when I received my K-3 kit with the DA-L 18-55 WR end of July: no USB cable whatsoever. Nor is that item listed on Ricoh Imaging's datasheet for the K-3, nor in the manual for that matter. So it seems to be official policy.
At first, I found that kind of irritating, especially since I had given away the (original) cable I used to have with my old K-7.
But then again, it makes sense, even if I don't like it. The thing is the K-3 supports USB 3.0, which *is* a cool feature but also entails that while the cable's PC plug ("A Female", in USB speak) is downward compatible with USB 2.0, the camera's socket only accepts a 3.0 "Micro B Male" plug (cf. diagram).
Now they could have included a strong reliable USB 3.0 cable, but that would have affected their price calculation and likely have made the K-3 more expensive, or they could have put a near-worthless flimsy one in the box (like that ... er ... joke of a 3.0 cable that came with my WD My Book drive recently) and risked antagonizing people over cheapo cables that quickly fail on them. (In fairness, the one I'm talking about still works, it just doesn't look the part.)
For my K-3, I wanted to be on the safe side and picked up a strong third-party cable the same day ("Hama" brand, if it matters). Cost me about a tenner, problem solved.