At least (?) that's in an app. But it's worse. A hotel told me it's sometimes plaintext over email.
https://arstechnica.com/information-technology/2023/02/myste...
https://arstechnica.com/information-technology/2023/02/myste...
Generally, though, more and more hotels shifted from faxes to API integrations via channel managers. But that's a whole extra step in sophistication.
Good times!