I think the demo video for Natal went to ridiculous extremes to showcase the technology. The "hand buzzer" thing to which you refer being one, the invisible steering wheel being another. It's an interesting technology but I agree with Natal's detractors in that tactile feedback is important in many gaming situations.

In my opinion, equating Natal with "hands free" is potentially a marketing mistake. But then again, "hands free" is more casual and that's a huge market so perhaps Microsoft is right. The beauty of Natal though is that it can, like the tech in this patent, do "hands on" too.

That said, Sony's patent seems to be something else entirely. It claims to be able to recognise objects in 3d space and presumably, orientation of those objects. I'm afraid however that that is where my imagination fails me. I can't understand how that level of tech could be more effective in a gaming environment than what is already available (or soon to be). Anyone have any ideas?

The system looks similar to Microsoft's Project Natal, but instead of driving with an imaginary steering wheel, players can use an everyday item like a plate.

You can hold "everyday item's like a plate" with Natal too. The difference is that you don't have to for it to work.