Just to be clear, resources like Google Maps should only be used to do a basic check for major errors, like if your coordinates are hundreds of feet (or even miles) off. These maps are simply not consistently accurate enough to use for getting coordinates for a cache placement. You should be using the results of your GPS device, as is stated in the guidelines.
I agree! Google Maps are not always that precise, but in combination with the averaging you WILL get a precise position. Collection a large number of positions in 5-10 minutes will give you a very precise position. The tests I have done with Geocache Placer using the tool on "Satellite Google Maps" in Denmark, in the areas where I have tested Geocache Placer, showed me that the average position was exactly where I was standing doing the averaging. So in my area the Maps are very good. The benefit of this tool is that the user can do the test himself, testing if the maps and the GPS position is showing the same. If this is the case, Geocache Placer can be used.
It could be fun if someone with a good GPS device could test this against a tool like "Geocache Placer". If I had an GPS device I would have done this myself :-)