Trust me. They know exactly where that prop is, where it's pointed, and how fast it's moving. Dolphin ain't dumb. 

But it's actually kinda sad to see a "wild" Dolphin like Beggar turned into a lazy moocher. And lemme tell ya he has it down to an art. He knows who's who and when he spies a likely target he'll limp up along side the boat, looking hungry & sad, like he barely has enough energy to propel himself. So, naturally, stupid people feed him. Which is expressly illegal btw. Pathetic.