I figured out how someone posted a weak ice point on Cascade. Regardless about how you feel about sharing your fishing spots, I hope we all agree that we would like to keep each other from a cold swim. This link explains how to make a mark. I think the buoy mark used by the last person to mark a bad spot is a good idea. When you put your cursor on this mark, they made a note- "bad ice" I would success adding a date, and perhaps removing them each spring, or when they are no longer relevant.
http://www.westernbass.com/article/boating-app-tip-2-edit-your-map-navionics
