So when i cross the border next week and his name is Ed, i should keep my mouth shut
I've crossed with a ton of seeds and 50lbs of blush tomatoes and ghost pepper salami, etc...to share and trade with friends and neighbors...(and get in return a 25b box of king crab legs from a commercial fisherman friend who LOVES tomatoes). He would bring up a dozen at a time from cool storage and had them all lined up in his kitchen watching them ripen and ate them like apples...adorable.
In all seriousness i can see the problems with contamination of soils crossing or introducing disease. In fact i recall a garlic issue a few years ago via suppliers sending off troubled stock. I always see in nursery on-line catalogs where some saplings cannot be sent to certain states.
If a person is sending another person a flat package of seeds as if a common correspondence, it would not bring up a red flag or even necessarily be wrong or dangerous. A return address from a nursery might raise an eyebrow if noticed.