First, I don't see the relevance of the half-mislabeling of a taxiway on a photograph intended to inform the public about how aircraft noise is distributed over a large part of Washington State. Sure, in both cases you probably had someone in their office, working to a deadline, making a quick decision and getting it wrong. But that photo is not intended to be used for any safety-critical task, and the person who did it was probably alone.
Second, The Aviation Herald is a valuable internet resource that provides unmatched coverage of aviation events thanks to the tireless work of one individual. Yet that individual (Simon Hradecky) isn't always explicit about his sources, nor does he have unlimited resources. But we can reconstruct his work. In this case, he posted 2239Z on 29 December. The only news item I can find that predates this posting is a piece in the so-called
Puget Sound Business Journal, stamped "1:59 PM, PST", on 29 December, aka 2159Z. The only person cited in that piece is an airport spokesperson.
So, either the airport sent out a press release, or some similar public information came out on 29 December, or (less likely) the PSBJ writer heard about it from his contacts at SEATAC (AvHerald calls it an "incident", but the FAA does not). All the hard information the PSBJ writer (Steve Wilhelm) had was Aircraft type, flight number, date and approximate time, and that it landed on the taxiway rather than 16C.
Now Simon goes to work. He calls his contacts at AS and the FAA, and gets confirmation; he collects the METARS, and he digs up the information on Flightaware, getting the registration number, more precise arrival times, and even the ADS-B track where you can see the sidestep gone wrong.
The last step is to listen to the audio, which is archived on LiveAtc.Net. Here's where he went wrong. He states:
An Alaska Airlines Boeing 737-900, registration N477AS performing flight AS-27 from Chicago O'Hare,IL to Seattle,WA (USA), was on an ILS approach to runway 16R cleared to land on runway 16R, when tower offered a visual swing over to runway 16C, the crew opted to accept runway 16C but aligned with taxiway T in between runways 16R and 16C and continued for a safe landing on taxiway T at 08:31L (16:31Z), no other traffic was on taxiway T at that time. Tower, maintaining routine communication, cleared the aircraft to cross runway 16L, the crew read that clearance back after a slight hesitation and maintained routine communication, too.
First, he reported that the Tower offered 16C; in fact, as you can hear from the recording posted above, AS27 requested the side-step.
Second, it is true that Tower later cleared the aircraft to cross 16L, but that's not the whole story either. Simon's carefully-worded statement sounds like AS27 landed, acted like nothing happened, and, at the moment they were cleared to cross 16L, they realized their mistake. Some have even drawn the inference that AS27 crossed an active runway (16C) without clearance.
In fact, that's not at all what happened.
LiveAtc's Seattle "Tower" feed is actually two frequencies, East (16L, 119.9) and West (16R/C, 120.95); On the feed, East has priority over West, and in scanner fashion, the beginning of each transmission is not recorded. If you listen to the recording posted above, you'll note that the controller on 119.9 is female and 120.95 is male. If you follow the recording to the next half-hour, you'll hear at 01:28 in the recording "27 left turn on November cross 16C hold short 16L", shortly thereafter (01:50) West hands AS27 off to East, and then (02:05) is instructed to cross 16L.
The "Ground" feed does not have archived recordings for this period, so we have no record of AS27 copying a phone number.
In short, AS27 was cleared for 16R, requested, changed to and was cleared to land on 16C; it then landed on T, and the mistake was known immediately (well, immediately after landing on the taxiway) to all involved.