Reading the number of responses has really opened my eyes to just how sensitive this topic can be. I am in agreement with some of the arguments on both sides. When thinking about it, it boils down to ethics.
Public water is open to all, you can't lawfully say "This is my spot". However, I can certainly see where a boater I fished with on day one would be a little more than p*#@ed if he were to see me with another boater on day two camped on that spot when he arrived! This is something I would not do, ethically it is wrong. Now further down the road, if I were fishing this same body of water with yet another boater and that person asked me if I had any ideas where to go, I don't think it would be wrong to give him this location. Is this a fair assumption?
Like I said in a previous post my use of the GPS is mainly to log my catch. Yes, it is also to learn water, but I would hope I can use that information in a fair way.