In airports you usually spend a lot of time by doing nothing, Rigorous why do you think it's a bad idea if they install them there?
Airports are stressful. I think people in airports are too preoccupied with checking in at the right time, taking care of their luggage, finding their way to the gate. What time they have left are spent with relatives or in the duty free shopping district. In short I do not think they are in the mood for checking their health before or after their flight.
honestly, this could be also useful for airport security staff member to extract passangers coming from another country with a disease which could spread out in the country. think about the pigflu, birdflu and so on.
OK, that is one good use-case I did not take into account. If you have ever watched Border Security: Australia's Front Line you know how stringent they are about biohazards.
Yes that last mention from SEELE is a real good usage .. I do think the devices should be more used for those kinds of services. More professional not retail.