Makes sense, if they are using SONAR instead of RADAR (Which also makes sense since RADAR wont' see some things SONAR pings off nicely, Like a Christmas tree in the road, and yes there is a true story behind that, but not today)
Some folks can hear SONAR.. I used to be able to hear it Even if it is supposed to be "Ultrasonic" (Do not know if I still can, have not listened for it).
Congrats on the new MH by the way.
Home is where I park it!