The Sharks know there will be food, but if you remember they are passive until the chum ball hits the water! They don't care that your in the water and don't associate you with the bait! If you read my posts that was my point, you are not the stimulus, just another thing at the feed! I have never said they don't react to stimuli, just that their is not the connection to humans that people fear! You know after the chum is gone you swim around the area for the rest of the dive! The sharks move on!