Particularly if I sailed on that body of fresh water. Really, I would given the corrosion issues on salt water....However, the added cost of getting that fresh water boat to my salt water sailing grounds would not be worth the added expense given the same boat.
I spent a week up on the lake recently and it was awesome....my dive gear, hobie cat, wave runner, windsurfing gear and even my body was given a nice, week long fresh rinse.
You can't fault those lake people for giving an edge to their sale