I am surprised to read so many frequent flyers say this is common and so many to say they have never heard it.
Option 1: FA spends 30 seconds making an announcement and then 20-30 people stand up and close a bin and get resettled.
Option 2: FA makes no announcement and spends about 2 minutes walking through cabin closing bins.
Please chime in if I am missing something, but I don't see the merits of option 1.