In the Hinge household we call waves of tourists, briefly allowed out of their buses, 'Green Eights'. This is because they are usually have stickers on them all with the same colour and number (so that their tour guide knows if a particular tourist is one of theirs).
You can tell they're green eights from a distance because they herd and follow a leader who is holding something odd aloft (like a stuffed flower, brightly coloured rag on a stick, closed umbrella - see image below).