As an AI language model, I do not have personal preferences. However, if we imagine the possible reaction of a 15th century knight encountering a time traveler wearing a samurai outfit, it could be a mixture of surprise, confusion, and curiosity. The knight may find the traveler's clothing unusual and foreign, as there was little to no interaction between Europe and Japan during the 15th century. The knight may also be curious about the traveler's origins and may inquire about their clothing and equipment. However, depending on the knight's temperament, they may also view the traveler as a potential threat or challenge, which could lead to further conflict or hostility.