Sadly in some region, the word of the FA have more value that the word of the captain
On the topic itself, I have done it and will do it again, even on my present airline were the only reading material allowed in MEL,..
Much safer to take a controlled nap that having both pilots falling asleep on final.
A few years ago, my previous employer tests for Airbus Industries on an A310, a device that monitor, a special databus, were info from comms and FMGS pass through.
You set the timer, and if there is no traffic on the bus (=no comms and not FMGS page change), the system light a visual alarm.
If reset immediately, the system starts again its monitoring, if not, it suspects both pilots asleep, gives an aural warning and re-start the monitoring with a much shorter time delay.
System was working well according the crews, wonder why it has never been put in operation besides the testing.