And also noticed no dust caps for the end of the lens . I for one would not really be happy with with a group of lenses rolling around in a bag, or to me it really looks like he is just switching from two lenses, I really was not paying that much attention.
I do a lot of switching from a 50 1.4, 70-200 f/4, 18-135, and 10-22. Different filter sizes in there as well. I keep the current dust cap in my jacket pocket, and do something similar, but I take the extra time to keep both ends covered. I have also been shooting a lot on a tripod, and one of the ones I use has adapters for quickly changing, and I picked up a couple extra, so I can swap from the collar mount of the 70-200 to the camera mount for other lenses.
This is also the prime case for a back up camera. Most photogs I see that do a ton of switching are wearing to cameras and they have their choice of lenses down to two for the most part