Thread: One up the spout

Yesterday, a bloke I know told me that he now carries his rifle with a round in the chamber but with the sear disengaged; as in, he holds the trigger back during chambering so that the chambered round sits with the firing pin pressing on the primer under spring tension, but not 'cocked'.
This on a Remington and he claims that because the bolt shroud covers ( sort of) the back of the cocking piece this cannot be struck in a fall.

When game is sited and he is ready for a shot, he simply lifts and closes the bolt to 'cock' the action.

He considers this 'safe practice', I consider it possible that if the 'butt' was thumped down on a hard surface the inertia of the shell against the pressure of the mainspring could cause the rifle to fire.

Opinion would suggest this to be unsafe, does anyone know from an engineering / physics perspective whether it is safe or not ?