There is an article in the Marin IJ today about homeowners in Mill Valley that build their landscaping and pool house on open space and MMWD land. Over 7,000 sq.ft. of improvements ended up in the Homestead Valley open space, sparking the outrage of neighbors and open space advocates.
This is a good example of why in many cases homeowners should consider surveys when working on fences, large parcels, or other landscaping near property boundaries. Should adjacent properties sell or if neighbors want to expand, encroachments can lead to frustrating legal conflicts and the possible removal of improvements.