The GP's point is well-taken. The company that produces this particular widget calls it an "underwater locator beacon",[1] not a "pinger".
To "ping" implies you are the locator, not the locatee, whether you are sitting in front of a terminal window or are running the active sonar[2] on a boat. You send a signal out and await a response, be it a reply (as in the case of the ping command) or an echo (as in the case of sonar).