What you often find in the States are a long bank of checkin computers where the checkin desks used to be. Behind the line of computers you get one or two "roving" employees to help the customers with problems. I think I am extremely computer literate but can still have stupid brain-fart problems with these machines, so I expect less computer literate people might have too. So although these machines are brilliant, you need humans to help out. They also have unattended computers dotted around the area for people with hand luggage to use. Look at the way Southwest does it at places like LAX, they know how to treat their passengers well, just copy them.