As Ken indication, they will rust eventually as the stainless mix is biaaed for structural performance.
18/8 stainless is 18% chromium and 8% nickel and often used in cutlery to make sure of it's rust inhibiting properties. With that would most likely come fatigue failure in many automotive structural components subject to stress and vibration. Those elements are reduced to bring a more steel and less stainless specification to components such as disc and exhaust items.
You can't really treat with any oil/lubricant based liquids thouh as it'll impair braking definitely. Just dry store is the most you can do.