[throwaway1269]

Visibility while diving can be super low and underwater weapons (mostly crossbows) are not that great. Also the dolphin is kind of a smarter shark and if you attack it's not out of the realm of possibility it will bite you in balls in retaliation. It's not impossible the might be arming dolphins with guns too against armed divers.

[pelasaco]

I think the scenarios of Dolphins armed with explosives that just explode when they bump into enemies a real one. Or sacrifice them to detect mines. But the whole The Dolphin detect the mine and then come back or Dolphin place a buoy in the back of an enemy diver with its mouth is nonsense