Max, I'm Suprised that wasn't passed along.
Much of the policies for securing the cabin were developed in the aftermath of flight 63, that was thought up on the fly, and passed to all US carriers as a suggested standard procedure in the resulting debrief and tightening of lockdown procedures that follwed that flight and the brazil assault on the UAL flight deck.... I wonder how much gets passed beyond the border... And then gets discarded because it wasn't "created over here"...
Not all crews follow the cart procedure, but they are supposed to...
Cheers
Wino