Delayed Disruption; Night Disruption

[Al]

Might be a little off-topic but:

Seeing we want realism replicated as close as one can, I have wondered how does one know in real life if a unit is disrupted? Basically if a unit is disrupted, what factors contribute to being seen as disrupted? Suppression, angles of attack on it, state of morale/ammo/food/command? Or visual indicators like people running and screaming?

One of the effects of disruption is decreased - 1/2, I believe - firing effectiveness so in real life one would notice a marked decrease in firing from the enemy.