That is exactly what happened at Netscape: a whole lot of nothing. Our engineers combed through the source of all our server products: web, email, et cetera. In the end, they evidently did a great job, and nothing of any note went down.
A conference room was converted into a kind of incident center complete with floor to ceiling world map to plot the locations of any outages. Someone even brought a satellite TV dish mounted on a tripod in case local terrestrial TV failed.
No lie, in the runup to that night everyone was concerned, but as it wore on, our relief was sweet.