I think it's a common misunderstanding worth bringing up here that probably affects more people than the falsehoods listed in the article. On roughly 3 out of the 4 times I've had a coworker run into a timezone issue (different person each time), their first impulse was to do something like what I described. (I stopped them early most of the times, so maybe they would have figured out it was the wrong way to go about it.)
Unix times show up in a lot of APIs and aren't always explicitly called "Unix times". People just see that at some point there's an integer value representing a timestamp, and the time string displayed to the user is some number of hours off, so they think they need to change that integer.
That's less of a "falsehood", more of a complete misunderstanding of what Unix time is.