Well, you don't get the benefit even if the offered reason was "hinkey". The Huakai free bag rules, available on the Hawaiian Air site follow. It's been years since Hawaiian's checked bags through to UA w/o collecting UA's normal bag charges. Relative to the Huakai benefit, a 016 ticket fails Hawaiian's first requirement and is probably the real reason why a free bag allowance wasn't in the cards. Plus, your HA# was not on the reservation.

3. Neighbor Island Checked Bag Benefit:

• Members receive one free checked bag on neighbor island flights marketed and operated by Hawaiian Airlines.

• Member’s HawaiianMiles number must be on the reservation before bags are checked to be eligible for the free bag benefit.
• Benefit is not available when checking in with a codeshare or airline partner.
• Member’s number may not be changed from HawaiianMiles to another program for any part of the reservation when the free-checked-baggage benefit has been used.
• Free checked bag benefits for Pualani Elite members, Hawaiian Airlines World Elite Mastercard cardmembers, and Premier Club members still apply.
• Huaka’i by Hawaiian free checked bag benefit is not combinable with other free bag entitlements.