Originally Posted by
username
Back to the topic...I am just wondering what the protocol is and thought it would be better if some explanation comes from the cockpit over the PA, as it seems to happen at least 70% of the time.
Except that's not actually true. In this very thread a United pilot said that most of the time they use the interphone rather than the PA to ask flight attendants to take their seats. The PA is only used when the turbulence is unexpected.