Some thoughts on Alma 55:11-15
Throughout the war chapters, there are many instances in which the Nephites trick the Lamanites,whether it be in taking over cities or freeing prisoners. I feel, that the reason for this is because the Lamanites were blinded by their own greed. In this particular instance, they just wanted the wine. They didn't care about guarding the prisoners. And then what do they do? They try and pull the same trick on the Nephites. Not the brightest idea if you ask me.