A little know fact about the Roman Soldiers Red Cape. It was psychological warfare.
Roman soldiers marched to all corners of the known world conquering for the Roman Empire. It would not be surprising that they would often sleep out in the open because they did not all carry tents. Only their Commanding generals. The troops all slept by an open fire. Thus their capes really served as Blankets for sleeping under the stars on those cold nights. The Roman Soldier's Cape was his sleeping bag.
The reason why they were red in color was to hide the fact from the enemy, should any one of them be wounded. An enemy force could not tell from a distance if the approaching Roman Army was weak from battle or had blooded wounded soldiers with them or how many. So if they were not certain that they could take them on, then they would avoid the Roman Troops all together if they did not have enough troops of their own for the job.