Don't usually jump too far out of my area (Seattle), but this is too crazy to pass up.
In our area, every major commercial FM, and most mediocre ones have at least a second site. A few have more than that. None of the alternates performs a well as the main, which I suppose was the whole point of building those sites in the first place.
We have a couple of AMs here that have separate night sites, mainly to position DAs where the additional towers could not be located at the daytime site.
A couple of our majors are running 27,000 watt transmitters on rotary phase converters, because of the cost to run a 3rd line up the mountain. Those converters have to be shut down a couple of times a year for capacitor replacement and other maintenance. Never do those stations mention they're not on their main transmitters, even though their alternate signals are far inferior. Matter of fact, their engineering is contracted and few at the stations have any idea what transmitter they're on at any given time. In the case of one of these, which simulcasts a 50kW AM with a full-power FM, you would never hear the announcers mention that one side or the other wasn't running at 100%.
What's probably more common these days, is power reduction or temporary site changes, caused by work being done on shared towers, as has finally been determined in this case. Tower companies are generally well informed as to where they can go and for how long. Radio stations know they have to cooperate when workers are on the towers. I've never had a station gripe about when they're reduced or moved to an alternate. It's life for a shared facility and everyone knows the only way to avoid it is to build their own stick on their own private plot of land.
In any case, all of this is part of life as a broadcaster. The notion that this might somehow be "news" or competitive fodder is interesting, but unlikely. I doubt a newspaper would tell their readers if one of their presses broke down and they had to contract with an alternate company to get their papers out.
One might also consider stations that run for long periods of time on STAs, due to variance from licensed parameters. I know of a couple that have been running 1/4 power for years, due to major tower issues. They don't make that fact part of their day, and its not part of any sales discussion I've ever been around. As noted, you're only looking at a 50% reduction in coverage, which probably pulls the fringes in somewhat, but not a lot more than that.