Yes, they can’t possibly show everything tape-delayed on a single channel. I’ve been watching tennis on Bravo all week. But the big events get tape-delayed coverage on NBC, and that’s something that seems really pointless when the result is all over social media and every sports website as soon as it happens. I think NBC should air this stuff live and then show it again in prime time if it showing it at those times is really so important. And actually this might point toward the solution to the OP’s question: the sports coverage that preceeded the attack would be pre-empted, but it might go up on the web with no fanfare once things had calmed down.
I think the answer to the OP is that if there was an act of terrorism at the Olympics, the events would be suspended in an instant. There would be nothing to show, tape-delayed or not.
This claim is made in the 1999 Oscar-winning documentary “One Day in September” so I wouldn’t call it an urban legend. (To be clear, the claim was the terrorists were watching the armed West German police advance on their dormitory via the news coverage. Not the later assault at the airport, which obviously wouldn’t even have a TV available.)
Anyway, if Ibn is correct, perhaps new research has shown that there wasn’t electricity in the hijacked dormitory. But it’s not like it’s an outlandish claim. It was being shown on TV, and the terrorists did seem to sense something was up (at least, that’s how it was presented in the documentary).
What is the purpose of cutting off the cell phone networks? I can imagine its usefulness in a hostage or standoff situation, but as a general response to any type of incident it would seem to be counterproductive.