I can see the ocean thing, but that's where you'd want it the most! On most ocean charters, the wheel house has the electronics (including gps) sitting in plain sight anyway.

If I take a guided trip, I normally have one of two reasons. I don't have the equipment to get there and just want to experience it (Marlin in Kona or Baja for instance), or I am trying to learn the water and looking for a teacher, not a boat ride. If the guide won't allow it, I find another guide. Frankly, in the few guided trips I have taken in the last 5 years, I've never been turned down.

A good guide can outfish me on a bad day. He has little reason to fear my arrival back at a hole he's taken me to. Just as long as I don't mention it here!