I agree that sending a radio message bears the risk of interception but I assume that the USN had the capability to encode and decode messages on each vessel(history buffs can prove me incorrect on this
). While this would not overcome the chance of the transmission being triangulated upon by the enemy, they would only get a rough fix on you. At present, I dont believe the game accounts for this whenever you send a status update or target spotted message. If the game did "hear" your transmission then it would add a bit of excitement as you could try to evade with whatever facilities you have left (dive & resurface etc) or you just play possum and wait to see arrives first.
A fighting chance is all I ask.