This is a great feature the the mavic pro and Mavic Air has built in. For shutting the drone off.  It is NOT intended as a way to hand catch and shut off your drone but a way for it to shut down in an emergency crash or bad landing.  

Emergency Shut Off Trick For DJI Mavic Air and Pro Drones

https://youtu.be/vfJBVymiUSs

Good day. Thank you for that footage. It is very informative.

Nice video! Maybe it is the official way to land the MA (check 6:23)

Didn't DJI disable this feature in a past firmware?

No.  It currently has this enabled as an emergency shut down.  If your drone is upside down on the ground it should shut down on its own.

Great video, Thanks for sharing!

You’re welcome.  

It’s a pretty nice feature so if you wreck the props stop if out of control.

Very informative.
Thanks for sharing.