Here's a pretty good account of Derby Line, Vermont/Stanstead, Quebec, where the boundary runs down the middle of streets (so crossing the street is an international visit) and right through buildings. I think that this is where the green house above is located. The border runs right through the library, marked with a black line on the floor.
Make sure that you watch the video on the ABC story below.
https://abcnews.go.com/Travel/wall-borde...d=37196875
Here's a Canadian (
Toronto Star) account of the same town(s)
https://www.thestar.com/news/canada/2016...urity.html
It's unfortunate that since 9-11, border security has been stepped up and now the place has lots of surveillance cameras and everyone is supposed to check in with the US or Canadian border people whenever they cross the line. Theoretically there are hefty fines and possible jail time if you don't. Given how illegal aliens more or less have impunity to violate immigration law as they wish, I'd guess that they don't really mess with local residents here that just make short visits to shop or see their friends on the other side. But if they see groups of people who obviously aren't locals, they might step in. The US Border Patrol guy they interviewed grew up there and knows everyone.
Not sure how they handle the people in the buildings sitting right on the line. I heard somewhere that the local border agents know who lives in those houses and don't mess with them going in and out. They don't have to report to customs before going to the bathroom. I have no idea who collects their taxes.