As soon as she booked, a recent guest gave her arrival time as "I am from [country] and arrive 5 o'clock." and asks the best taxi prices from the airport. I like this sort of guest! I let my guests know that I will watch online for any updates to their flight arrivals so that they don't have to worry about trying to contact me about the updates. (It also means that guests are less likely to use the My Flight Was Delayed excuse - but I don't tell them that!)
Then I double checked the flight times. Nothing remotely matches her arrival time via any of the usual routes from her country.
As English was not her first language, I thought that perhaps she had given me her best guess as to when she would be arriving at my home. I searched flight arrivals again for anything arriving about 2 hours earlier. Still nothing. Maybe she was stopping in Australia for a couple of days first. There are several trans-Tasman flights arriving around 3pm or 5pm, so I asked for her flight number.
She promptly replies. I thank her, double check the arrival times and realise that she was arriving on a direct flight at 5am!! More communication follows!