Always such a lottery when you cross the border. You just play a straight bat and declare it all, be it liquor, tobacco, or general purchases. Some days they're not interested in collecting taxes and you're waved on, other days it's the full program.
I lnow though that over the years I've paid a lot less in taxes than the official rates, by being upfront and declaring, giving clear, nothing to hide answers. Border guys see themselves as protectors keeping out danger in the form of drugs, guns, terrorists, criminals, diseases, animal pests. They don't see themselves as tax collectors, and will often waive those opportunities in favour of what they see as focusing on their real.job. You just cop it sweet on the occasions they do decide to work the revenue part of their role.