I've read that Taiwan doesn't pre-announce diplomatic visitors so that Chyna can't pressure. When M. Pompeo went to Taiwan back in March:
https://www.reuters.com/world/us-former-top-diplomat-pompeo-arrives-taiwan-calls-it-great-nation-2022-03-02/
We didn't hear about till after he was there…
So anons… why pre-announce Pelosi?