Here's a new one for me... about 26 hours before my flight today, my partner received a text message notifying him that due to an equipment swap, we had been downgraded from PS to C+ (a text message he ignored). On the other hand, I didn't receive any notification and wasn't aware of the downgrade until I tried to check in 2 hours later.

I went through both of our SM profiles, and neither seem to have any option to opt into or out of text notifications.