This is terribly dangerous. Thus far, they've been lucky - nobody has done something wrong or stupid. That said, it cannot last. Putting industrial robots like this on a moving track, and then putting them close to humans at high speed is a recipe for disaster. This system has a 6 meter by track length operating envelope and moves over 4 meters per second. It also has control over 110kg of material - putting its weight in the 2000kg range (minus the track).
There are safety systems available, but none that are commercialized that will allow humans and robots like this to exist in incredibly close proximity with any expectation of safety. Some of the recent research we completed at Carnegie Mellon points to a future where this is possible: http://www.youtube.com/watch?v=-_Xc4yq-rz0
But we're not there yet.