Originally Posted by
Dirtdiver
A "distressed passenger" without a seat assignment. They may have missed a connection (thanks DCI) or maybe another airline canceled a flight and DAL agreed to take a certain number. They show up unexpected at the last minute and crush any hope you had of getting on a flight.
Those are HKI ("I"nconvenienced ).
After a certain percentage of seats are sold, the seat #s are not assigned.. Gives the gate agent some flexibility to seat families together, put Stretch in the emergency exit row, give the fraud service dog in its own seat, etc. The folks who weren't assigned (and can't choose) their seats online are HKs.