Robert Weintraub of the Columbia Journalism Review reports that many NBC Olympic announcers are sitting in New York calling the events that are taking place 12 time zones away:
Here is where the Peacock has been honest—announcers in New York, not Beijing, are calling many of these events. An analyst and a play-by-play man sit in front of large monitors and call the action off TV, just as many of us do in the privacy of our homes. (Wait, did I just admit to that?) Although the home viewer would be otherwise unaware, NBC has nonetheless had its announcers state up front and often that the action is being called from the States.
If they make it clear upfront that they are calling the event from New York, there really isn't any conflict or deception. I haven't heard such an announcement during the coverage, but I'm not watching the Olympics wall-to-wall. In this era of cost-cutting, I'm not too surprised.
It reminds me of a practice in the 1930s and 1940s. Local baseball announcers would not travel with the team for the simple reason that the technology wasn't really in place to call a game live from a remote location. So they would work out-of-town games sitting in their studios and using reports from Western Union!