I have no problem with customs questioning anyone appearing to cross the border in an illegal/suspicious manner. Detaining that person without further proof of misconduct would be a different story. If someone appears to be trying to enter into our border from Canada I'd hope they would be questioned on the Canadian side as well.
So for me at this particular cache, I'd rather approach from the road and go through customs if needed rather than take the chance of having to forced to discuss it in the middle of the woods. Feel free to approach it the way you desire.