he meant guard posts on tiny little islands with only maybe 5-10 guys on it. usually in the south china sea. islands can be as small as 1 acre, a piece of rock that strategically located. they build a small fort on it and raise it high enough that tides won't affect it. and give the troops a small boat and food/water. taht's it. the bigger islands would be maybe a few hectres, still not very big, with maybe maximum 20-30 troops, those guys gets an artillery piece or two, and maybe a few small boats. in canada and US there's no need to so many border guards, since both of their longest border is the 49th parallel, which is the world's longest unarmed border. there's nothing north of canada, so there are just a few radar stations and icebreakers for the winter. both countries have oceans on both sides, so coast guards are more important.