This is supposed to demonstrate their good intentions.
6 seconds sound clip from the Cannibal Holocaust movie soundboard.
You can hear this line at 00:25:34 in the Blu-ray version of the movie.
Quote context
[...]
- Instinct... Something says your friends have made quite a mess of things.
- Wait! If Miguel pulls this off, I swear I'll buy him a bottle of whiskey.
- This is supposed to demonstrate their good intentions.
- There, they're going to show themselves now.
- Where the hell are you going? They're going to lead you into an ambush.
- No, this is a sign of a good professor.
- Yeah? You could a fooled me...
- They just want to show us they are brave warriors. And they want us to follow them to the village.
[...]