It is a defense to pros­e­cu­tion under Sec­tion 7–1‑17that a per­son appear­ing in a state of nudi­ty did so in a mod­el­ing class operated:

(A) By a pro­pri­etary school, licensed by the State of Illi­nois; a col­lege, junior col­lege, or uni­ver­si­ty sup­port­ed entire­ly or part­ly by taxation;

(B) By a pri­vate col­lege or uni­ver­si­ty which main­tains and oper­ates edu­ca­tion­al pro­grams in which cred­its are trans­fer­able to a col­lege, junior col­lege, or uni­ver­si­ty sup­port­ed entire­ly or part­ly by tax­a­tion; or

(C) In a structure:

  1. Which has no sign vis­i­ble from the exte­ri­or of the struc­ture and no oth­er adver­tis­ing that indi­cates a nude per­son is avail­able for view­ing; and
  2. Where, in order to par­tic­i­pate in a class a stu­dent must enroll at least three (3) days in advance of the class; and
  3. Where no more than one (1) nude mod­el is on the premis­es at any one time.