We have been over the limit several times, and inform them during the "interview" at the border. I think since you are just passing through, they let us go without the duty. It must not be much or worth the paperwork. But we were 25% over the limit, not 400% per person.

It would be interesting to find out if someone has been charged and what the rate is; most of the time I think it would be worth it.

Now, don't stay in the U.S. and decide that you want to pop over the border to see "something" the night before your trip right across the border, then try to re-enter the states with your full load of liquor....for some dumb reason, they didn't like it at all. U.S. Customs.... gotta love em.