I was suggesting that it be in hand, in situations of a solo-officer stopping a vehicle with multiple occupants. Special-situations require appropriate measures.
PPL in the USA, are loath to see the guns out in the open, ready for use. This is not the case in europe. Airports and other vital facilitys are protected by armed guards/soldiers/policemen. The weapons usually carried are light machine-guns and assault weapons. Generally groups of two, one of the "caribini" has the weapon in a two-handed port-arms (count 2) stance, while the other might have the weapon slung/slinged on the shoulder. I have never observed a situation in that both carabini had slung the weapons at the same time. Observing the crowds interaction around the carabini...they seemed to take no notice at all, no more avoidance than one would normally take to walk around a potted-plant. As the carabini are "relieved" the 2 original men face outward from the newcomers, weapons at the ready...while the relief squad removes the clips, check them and reinsert the clip to the weapon.