19.4.1 An airline shall have the following obligations in the event of an oversold flight:
(i) ensure that the smallest practicable number of persons holding confirmed reserved seat on that flight are denied boarding involuntarily;
(ii) request for volunteers for denied boarding before applying boarding priority.
19.4.2 Any other passengers denied boarding except in accordance with Section 19.4 above, is considered for purposes of this Regulation to have been denied boarding involuntarily, even if the passengers accept the denied boarding compensation. Volunteers shall be compensated in accordance with Sections 19. 8 and 19.9. (Compensation Provision), such assistance being additional to the benefits mentioned in this paragraph
19.4.3 In relation to each passenger solicited to volunteer for denied boarding, no later than the time the airline solicits that passenger to volunteer for denied boarding, the airline shall:
(i) advise whether he or she is in danger of being involuntarily denied boarding and, if so, the compensation the carrier is obligated to pay if the passenger is involuntarily denied boarding ;
(ii) disclose all material restrictions, including but not limited to administrative fees, advance purchase or capacity restrictions, and blackout dates applicable to the offer before the passenger decides whether to give up his or her confirmed reserved space on that flight in exchange for the free or reduced rate transportation.
19.4.4 If an insufficient number of volunteers come forward, the carrier may deny boarding to other passengers in accordance with its boarding priority procedures.