I kind of agree, some companion clothes should be limited to the companion it belongs to. But for the freedom of an open world rpg, somethings i feel should be free and unrestricted, such as taking someone's clothes and wearing it haha. But it is a githyanki outfit, I feel like it should be in the fine details that it could lose some effectiveness when the wearer is not a githyanki. Much like the gloves of the Absolute. Only a bearer of the mark of the absolute can wear them without getting bane.