Not all lakefront properties are the same. MANY developments here in florida have lakefront property. The lakes were dug to make the house pads. Anyway, if the lake is surrounded by homes, then the homeowner does not own out to the middle of the lake. In fact, every home on the lake has an easement which allows any person living on the lake to be able to walk the entire shoreline w/out trespassing. This means I can walk out my back door, walk to the edge of the water and walk along the bank behind as many houses as I want and it's not trespassing. Sure, the homeowners can fence their yard, but the fence can't go to the water's edge. Usually it's several feet from the waters edge up towards your house that is "common" property.
I'm not saying this is true to every development, but it might be wise to check with your HOA, if there is one.