In part because of the additional 3200 base miles and in part because of the $100 fare difference, I decided to book my February HK trip SFO-SIN with a stopover in HKG on the return. I arrive in SIN on 2-7 at 11:55 PM (on UA1) and leave for HKG the following morning at 7:40 AM (on UA2). My original plan for the eight hours was to leave the airport for a bit just to get some air and then catch a few hours of sleep in the transit hotel back in the airport. But, it occurred to me last night that there might not be anyone at UA to check me in in the middle of the night. If that's the case, I suppose I could just stay in the transit area for the whole eight hours. At any rate, I'm a bit unclear about official policy on these matters so any insights/ advice would be greatly appeciated.