Don't tell them you are a US citizen of course, but there are no issues purchasing seeds in person in the Great White North, Eh. I've never found a shop in Niagara Falls, but Toronto is loaded with places to find seeds, and the shopkeepers are SO friendly!

Seeds should not have a smell of their own, but you don't know what was on someone's hands when packaging them. So be cautious.

BTW we can't get into discussions of transporting seeds across international borders here, sorry.