Sometimes you run into a "stickler" border agent who seems to have an axe to grind. I crossed the border back into Canada last week and, when asked, declared my 1 full 1.75L bottle of Whiskey, 1 case of 24 beer cans + a part bottle of Whiskey(7/8 full 1.75L), a part bottle of Vodka (1/3 full 1.75L) and 6 loose cans of beer. Mainly left overs from a winter spent in FL.....
99% of the time, the border agent will wave you thru with that amount of alcohol but this time, the agent sent me in to pay the extra duty on the overage amount ($28).
Yes, I was a bit over my duty free limits after being away for 6 months but what a pain! The Customs office in Windsor isn't really set up for pulling over a large RV/truck combo. The large truck inspection area was full so I had to back out since there was no room to navigate the tight space in the car section.
You don't dare express any dissatisfaction with the border agent's decision since they are likely to send you in for a full, "rip you apart" inspection at the least provocation.