AKs arent exactly great for rapid mag changes anyway - I doubt the extra work to line up two neatly side-by-side would be worth it to your average Liberian irregular. Plus, you are dealing with people who improvise with whatever materials they can scrounge.
For the most part, the "soldiers" fighting are very poorly trained and disciplined when it comes to fighing as a unit. I have heard stories of some very brave and talented individuals - but "Rambo" was a movie, not reality. Discipline and teamwork are required for an effective fighting unit.
I have a friend who is a vet of the 1997(?) UN interdiction in Liberia (for those that may not know, that was almost parallel to the situation this past month, but it was Charles Taylor's forces who were closing in on the seated leadership). He said most of the soldiers they fought against were poorly disciplined - the trick in a fire fight was to just take cover and wait - before long they would consume nearly all of their ammo, at which point you could maneuver your forces to more advantageous positions. Apparently, they took "spray and pray" to new heights.