The University may not prohibit any faculty or staff member from (i) displaying political buttons, stickers, or patches while on University property, provided that such display by any member of the faculty in an instructional setting is for a purpose relevant to the subject of instruction; (ii) attending a partisan political rally, provided that the employee is not on duty; or (iii) displaying a partisan bumper sticker on his or her motor vehicle.
110 ILCS 660/5-155