There would be ones (IPCs) in Mandarin, on the rows of it, in the arrivals zone, but new comers, or first time visitors wouldnt know about it, that they can fill it out later, of course, need a biro/pen.
But then, apart from the IPC, then there is the smartgate question, that one is in English only.
First you have to go to the shoulder high machine, which prints out a photo of/from your passport, on flimsy off white thin yellow paper... then to the machine that has the bright light to scan face...
But that couple would probably have gone to a staffed counter, and they would have gotten a Chinese (Mandarin) ABF speaker to converse with them.
But as they would have had their passport shown to check in at HKG, guess ABF would have known the couple was coming on the flight.