Not sure if it is SHEENA but hadn’t seen this before.
Last night ATL-SRQ (DL 1878) I am in 2B and at the end of boarding there are 2 seats left in F. GA brings up one person from Y and I can hear her tell the FA she will be bringing up 11A also (think it was A but definitely row 11).
A DL captain in uniform exits the cockpit almost simultaneously to this and the GA tells him to take any open seat in the back. The captain asks what about this one (it is 3B behind me) and after a few second pause the GA says go ahead and take it. Door closes and 11A is obviously not brought up.