I'm going to throw our name into the growing swell of disapproval. Besides the importance of being able to see names in our calendar, we use an automated lock code generator/programmer which both generates codes based off phone numbers and then texts it to the incoming guest.
For the time being, I've changed how codes are generated (now off date instead of phone number) and will manually notify guests of their code.
We're fortunate that we only have one listing--I cant imagine how many other hosts in more complicated situations are handling it!
I'll be opening a trouble ticket with Airbnb, even if the response is the "It's not our problem". I kind of expect soon somone will show up to work, realized their error they made, and quietly change it back. And we'll all just breathe a collective sigh of relief.