Another travel firm who organise South American tours let the tour go ahead when 4 people book, that is their minimum. Up until then, the tour can be cancelled. Luckily we had 8, just as well as timing for my 55th birthday Rio on NYE. No other firm catered for that date in Rio.
I heard that there were 12 already for the tour to Route 61- woo hoo, we are going 🙂