There's been quite a few studies done on it, and one of my professors actually gave us a few pictures as demonstrations (god i love mr epps, great man). Out of 5 pictures, I picked out 4 of the 5 differences. I was the highest in the class, most averaged 2. It's amazing what the eye wont notice, sometimes completely obvious things such as wings missing off an aircraft.
If I can find some of the pictures, I'd be glad to put em up. They're pretty crazy.
In short: I believe it. Though I dunno about an example that requires direct communication/contact. Notice though that they -have- to put the focus on the map, if during the switch the person is interacting with the speaker, it'd be ruined.