I have also noticed this. I'm not sure if its so much a bug as to a couple factors including line of sight and noise created, I'm assuming the Z's view range is like how a headlight projects light very narrow to really wide the farther away. Also it does seem u can sneak right up to one if u keep out of there LOS and not make to much noise, and if your in a house and not moving and they come they prob saw u threw the window I've noticed I've been spotted a couple times that way. I'm not sure though since they can move threw wall at the moment can they see threw them too so u cant lose LOS unless u get out of there view range. And the Biggest factor remember its a simulator survival game not at all suppose to be easy at all the more real the better

I feel that you shouldn't be able to put the same container into another of the same type. Since they are the same dimension it wouldn't work but different styles should fit into one another, But to the backpack in a backpack, if u store a empty backpack in another it should only take half the amount of slots as it does at this point in time, but if you chose to put any amount of items in the backpack it should retain the amount of slots each one takes up as of now. Reason being a empty backpack folds up since its fabric and one with anything in it will not.