An off-duty Flight Attendant reported while dead heading the aircraft had an issue with the landing gear and offered to assist with safety procedures but was denied.

Narrative

The captain advised via PA that there was an issue with landing gear and instructed the crew to perform a Prep for Land Evacuation demonstration. At no time was the entertainment system switched off prior to; during or following the demonstration. Once the demonstration was complete I went to the aft galley; where only 3 FAs (Flight Attendants) sit; and offered to be a 4th FA and sit at jump seat and assume FA #8. I was in uniform and willing to assist. A short while later the Purser came to the back galley and informed me that she only wanted working" FAs to be involved and asked that I return to my seat in the cabin. As the aircraft approached the runway there was no command from the Flight Deck to assume the demonstrated brace positions which made something of a mockery of performing an evacuation demonstration. After landing and deplaning the DHD (Deadhead) FAs were then converted to work the sector departing some 5 hours later at XA50 landing in ZZZZ airport at XK33; meaning extreme fatigue ensued due to being awake for approx. 27 hours prior to landing. The operating Pilots and FAs were released from duty following the incident yet the DHD crew onboard were not afforded the same courtesy even though they had less hours available to them and had experienced the same situation."