**Yes, yes, and maybe.** The island in question is [Hans Island][1] and is disputed territory between Canada and Denmark [due to some historical quirks][2],

> According to World Atlas, Hans Island is located in the middle of the
> 22-mile wide Nares Strait, which separates Greenland, an autonomous
> territory of Denmark, from Canada. Due to international law, all
> countries have the right to claim territory within 12 miles of their
> shore. 
> 
> As such, Hans Island is technically located in both Danish and
> Canadian waters. World Atlas notes that the island was decided to be
> Danish territory by the Permanent Court of International Justice of
> the League of Nations in 1933.
> 
> However, as the League of Nations fell apart in the 1930s and was then
> replaced by the United Nations, the ruling on the status of Hans
> Island carries little to no weight.

It is true that the militaries of the respective [claimants visit the island and both leave their national flag and schnapps or whiskey][3] it is unclear if these are meant as gifts or as territorial markers.

> In 1984, Canadian troops made a fateful voyage to Hans Island. In
> addition to planting Canada's flag in the rock, they also left behind
> a bottle of Canadian whisky. Just one week later, a Danish official
> visited the island, replacing Canada's flag with Denmark's and
> replacing the whisky with a bottle of Danish brandy. He also upped the
> ante a bit, leaving a note that wryly welcomed visitors to Denmark.
> 
> "[W]hen Danish military go there, they leave a bottle of schnapps,"
> Danish diplomat Peter Taksøe-Jensen tells WorldAtlas. "And when
> Canadian military forces come there, they leave a bottle of Canadian
> Club and a sign saying 'Welcome to Canada.'"


  [1]: https://en.wikipedia.org/wiki/Hans_Island
  [2]: http://www.businessinsider.com/canada-and-denmark-whiskey-war-over-hans-island-2016-1
  [3]: http://www.mnn.com/earth-matters/wilderness-resources/blogs/canada-denmark-wage-whisky-war-on-rocks