Yes, that's what I had to do for meetings that the organizer thought were important enough. Also, in very sensitive areas special rooms with anti-eavesdropping gear are common [1].
> I could turn it off entirely, but what if someone needs to call me for an emergency?
But you would also not be reachable if the killswitch is active ;)
Don't get me wrong, I think a killswitch can make a lot of sense for highly sensitive areas (R&D, politics, military, ...), but I don't think Fairphone 6 are the devices that target this demographic and thus should not include one. Furthermore, current "offline" measure seem to mitigate the problem okay enough to not need such a killswitch - else we would already have phones with such features. And lastly, killswitches can only mitigate parts of the features modern spyware [2] implements and does not protect from simple human-based errors like the United States government group chat leaks [3].
[1] https://en.wikipedia.org/wiki/Sensitive_compartmented_inform... [2] https://en.wikipedia.org/wiki/Pegasus_(spyware) [3] https://en.wikipedia.org/wiki/United_States_government_group...