Lakes and rivers still resolve

A lake is still inside a country.

GET /point?lat=35.62&lon=-80.95
{
  "latitude": 35.62,
  "longitude": -80.95,
  "country": "US",
  "country_name": "United States",
  "state": "NC",
  "state_name": "North Carolina"
}

That coordinate sits on Lake Norman, not the shoreline. Water resolves to the country and state around it the same as land does.

Open ocean is the only null

Place fields only come back null out in open ocean, where no country or state surrounds the point. A lake, a river, a bay ringed by a coastline, all resolve normally, because every one of them sits inside a country's borders even while the coordinate itself is wet. A river forming a border is the one edge case worth a second look, the two banks can resolve to two different countries a few meters apart.

Try it

Call /point on any lake and compare it to a coordinate a mile inland. Same fields come back either way, wet or dry.