I think the fisherman story was retaliation by Canada Customs for US Customs upping the entry requirments into the US, which has been ongoing back and forth since 911.
From Waterdown Daily Times, June 21, 2011
The State Department said this morning that Canadian border officers had the law on their side when they seized an American fisherman's boat and fined him $1,000 for fishing in Canadian waters without registering at customs. In fact, they could have made him pay more, the department said. In a statement, the State Department said the Canadian Border Services Agency was acting within “longstanding regulations” by penalizing Roy M. Anderson, the Thousand Island Park resident who was snagged by Canadian officers while fishing, unanchored, in a favorite spot in the Gananoque Narrows. All foreign boaters must report to Canadian authorities upon arrival in Canadian waters regardless of whether they anchor their boats, the State Department said, echoing the Canadian government's position. North country boaters have long been under the impression that they did not have to report unless they anchored. But the only exception, according to the State Department, is for boaters traveling through Canadian waters from one U.S. point to another — and without stopping along the way. “Intransit movement must be continuous, uninterrupted and without delays or stop-overs
So it looks as though, if you are sailing continuous, you can cross over the border and back again without reporting in. The problem occurs if you stop in one spot as you would while fishing. All technical parts of the law and the above may have been an example made by Canadian officials to prove a point?
