I guess my experience on the rivers of the great loop was not the same as some others. The big boys called me 6 or 7 miles away telling me their pass intentions(and I show up on their screen as a pleasure vessel). Did they all call me, no, but I know they saw me and knew I was there, which is definitely an added safety factor especially in limited visibility situations during bad weather where clutter on a radar screens can blot out a target, or on a turn where topography will do the same thing. If I want to be stealthy, I have the ability to turn off my Tx. Even when flying and everyone has a transponder and they are controlled by center, I can tell you I have been in IFR situations where even controllers have made human errors which as they say could ruin your whole day. Just saying for my MONEY give me all the safety I can get, which includes a transmitter.
Dwain Dumas
R-25 Lydia