Take those tips with a grain of salt, as this sort of conventional politeness strategy is heavily dependent on culture, situation, and sometimes even individual*.

I predict that those tips would work poorly with people from cultures where negative politeness (“don’t burden the others”) is valued over positive politeness (“show appreciation towards the others”). This is fairly common in East Asia for example, but even here in Latin America I got a few people rolling their eyes at “biztalk” like “obrigado pela paciência” (thank you for the patience) over a simple apology.

In special, I can picture the centre advice rubbing a lot of people the wrong way, as it’s basically the writer lifting a burden from one’s own shoulders (struggling to word something) by creating a burden to the reader (“I expect you to be available offline for a meeting”).

*if anyone wants to dig deeper into this subject, check Penelope Brown and Stephen Levinson’s Politeness: Some Universals in Language Usage. It’s a bit of a technical read for Linguistics (more specifically Pragmatics), but I got plenty laymen who love the book.