Local cops hassle you for knives because they're charged with keeping the peace. International customs doesn't give a shit about state or local laws. They're just looking for contraband items.
Hunters and fishermen take so many rifles, shotguns, skinning knives and gutting knives across the Canadian/American boarder that they mostly don't look twice at any knife that looks like it's part of your gear, unless you look like you're looking for trouble.
On my last overseas trip I bought a $3 switchblade in Moscow which I kind of planned would get confiscated (I wanted to test the system), but I brought it all the way home through half a dozen border searches and into a federal building in DC without anybody looking at it twice. It had a healthy coating of cheese, peanutbutter and breadcrumbs, and went into my pack when I thought I'd be going through a metal detector. No problems!
Your results may vary.