http://news.bbc.co.uk/1/hi/world/americas/8523894.stm
Well this is interesting. Even if it isn't a blockade in the normal sense if Argentina does get its way and the rest of SA joins in then diplomatically it is a rattling sabre.
I don't know how it can be policed though. Also what are they considering territoral waters? the 12 mile limit or the 250 mile limit?