They are in big trouble if flying Y on EK as EK specifies 3 hours check-in required for Y pax, per their condition ofhttp://www.emirates.com/conditions/Contract&PassengerNotices.pdf carriage

Of course it is an absurd policy and rarely enforced, but they would not be eligible for IDB if the flight is overbooked and would need to buy a new ticket if they arrive after 7:10pm at the EK check-in counter!!!! The joys of flying some airlines. I have seen EK strictly enforce the check-in requirement when it suits them, so this isn't a theoretical concern. Try switching to another airline if at all possible to avoid problems. If they are flying F or J then the check-in cutoff is 1 hour before departure (even that is pretty unreasonable at HKG, I have never checked in that early when flying CX F, 30 min is generally fine).