Interesting. Looks like they are available for sale:
As to how they work, I would imagine a two-piece hinged bottom supported by reasonably stout spikes with springs keeping it under tension so it tends to remain closed. Possibly a second or third set inside, higher up in the bag.
You wouldn't be too worried about scratching or damaging the target bag - it's the contents you want.
It would have to be a sturdy mechanism, as you don't want the target bag protruding out of the bottom of the booster. Looking at the video, there seems to be a bit of the captured bag visible underneath.
Regardless of how it works, I think that the lesson is to keep your bags secured. I had a friend visiting London, stopped for a coffee, put her bag down under the table with camera, passport etc. inside. She was able to view the security footage later on. Someone sat down opposite, kicked the bag further along under the table to where an accomplice picked it up and left.
Tourists are easy marks, because they are generally insured and aren't likely to get the police involved.
Just curious about the mechanics of it all!
