About those Crossed Arms
Both arms are folded together across the chest as an attempt to put a barrier between the person and someone or something they don't like. . . Crossed-Arms-on-Chest is universal and is decoded with the same defensive or negative meaning almost everywhere. It is commonly seen among strangers in public meetings, in queues or cafeteria lines, elevators or anywhere that people feel uncertain or insecure.
Bottom line with crossed-arms-on-chest main Melania Trump message: she's not coming out and you're not coming in.
When the crossed arms then become the Double-Arm-Grip as Melania Trump is posing, additional reinforcement is achieved in a form of self-hugging. Westside Toastmasters explains that in extended, hostile debates, the arms are easily gripped so tight that one's fingers and knuckles can turn white, with blood circulation being cut off. The pose shows a very negative attitude and definitely a message of "I do not want to be standing here."