Transfer Files using Bump

I'm always fascinated by Bump. I don't know a single person (of the 100M downloads) that uses it. But those numbers they post make me wonder why.

I once built an app on their API for a hackday, and I had to film the demo because I could never get the devices to connect via a bump. It would happen like once every 5 tries.<p>Just installed it again to see the mobile to pc bump, and although the web app picked the device, my phone never got a confirmation. Considering I still have to download the pictures from their servers, Google+ instant upload does a pretty nice job in this department. Until NFC.

Of course, all of this is superseded by NFC. Bump is really only relevant on platforms without NFC. I'm looking at you, iOS.

Im curious, If I can steal the file from the person next to me at the starbucks, If I hit the space bar at the same time?

is the physical bumping part a gimmick or require physical mechanism?