The E&E bag is the first component you put on and the last you take off.
It is part of the equipment loading rationale of most direct action military forces.
The E&E is part of your First Line gear. It may contain pistol ammo, emergency ration, compass, survival equip, extra map (with coded rally points and false egress routes), etc., etc.
This, along with other equipment, would never leave your body while enroute to/from target. You eat, sleep, and s**t with it.
If you remove your Second/ Third Line equipment (or ditch/lose it) and are stumbled upon by the opposition, you may have to "di di" without the benefit of all your gear.
The E&E is intentionally small so as to be relatively comfortable (therefore, no temptation to remove for the sake of comfort) but care must be taken in its assembly that it still meets valid contingencies effectively.
Generally, civilian uses would allow for bulkier, more comprehensive inventories in an E&E pack.
Caio, Rob