Before I discuss this issue, I am aware of the command STAY CROUCHED in the command menu. This topic will cover the need for more advanced AI stances.
When ever the player controlled AI is stationary, their primary stance should be crouch ( unless a command overrides it or their position in cover requires them to be standing). In a real combat environment, we never stand up unless we are moving because it exposes us to enemy fire. When using the bounding technique, one fire team holds their position while another advances. If you are in a moderately safe condition, the over watching fire team can stay in the couch stance. When under fire, they will be in the prone ( which Arma already has).
Only player controlled AI should be effected by this. Possible enemies that could utilize this technique are special forces.