I assure you they were well aware of what would happen if they did that.
I've been to one of the major sacrificial areas in South America. It was one of my bucket list items that I dreamed about as a child, this of course being in the days when schools taught basic history. Reading about the history there, I could see in my mind the steep sides of the mountain descending down into a hidden caldera filled with dark water. I imagined seeing the rituals, the sacrifices and the buttload of golden treasures dropped into the lake as an offering to their various deities. ;D
In the end, it looked very similar to what I imagined. The actual site was far larger than what I imagined, though. Back then, we didn't have as many photos available so I didn't know what it looked like until I saw it for myself 40 years later.
The site was "El Dorado"...the real one. No, unlike my childhood fantasies of discovering golden treasure, I didn't even consider diving into the dark water...*shiver*
