I believe a civilian has portscanned the whole Internet before via the same thing: http://internetcensus2012.bitbucket.org/paper.html

I don't get all the fuss about portscanning is either - anything connected to the Internet will be subjected to packets sent to it because the Internet is public; if you don't want others, government or otherwise, to know that there's a machine present at an IP, then it should be your responsibility to configure it so it doesn't reply.