I'm seeing some mixed posts saying to disable the VPS over water but on other posts it says that the VPS can get disoriented only a few feet above water. Can anyone clarify: Below what height should the VPS be turned off if you are not over just water? For example there is a lake I fly over, and I typically will fly 400' over it. I can see the edges of the lake in view along with little islands in the middle. Is it safe in that situation to keep the VPS on? Thanks for any expert advice.