You’re probably also making the (mistaken) assumption that the sticks operate like a big city, where nobody knows anything about anything. Too close to the big city, there are too many prying eyes who don’t mind calling the authorities. In the rural areas, strangers probably stand out because everyone knows each other. In the areas between Quebec and Vermont where people try land crossings, I understand it’s quite common for the locals to call about people they think are suspicious.
I assume that boats have to have registration numbers on them, so the autorities are going to wonder if you just zipped up an down the Detroit river like everyone else and eventually pulled up to an American dock with Canadian registration numbers. Going the other way, the Canadians are looking for smugglers bringing things like handguns in, and there is a strong cooperation between the two forces. If you put ashore in the middle of nowhere, then you also have to drive to and away from your journey points unnoticed.
I’m sure the border patrol loves to test any nifty new gadgets in the high traffic areas too - rumour has it the areas most used by smugglers (drugs and illegal immigrants, typically) are flooded with the footfall sensors and other toys developed for the Vietnam war.
In fact, the biggest problem with this is the Mohawk reserve between Canada and the USA where tensons with authorities run high, and smuggling is a legitimate and lucrative form of protest.