Most countries boo the Hell out of American teams at the Olympics.
I've been to two Olympics in other countries now, Barcelona, Spain and Athens, Greece.. and our country is booed to no end by other countries, at least at the events/medal ceremonies I attended. Both times, myself and the friends/family I was fraternized with the people around us, and usually always those people were from other countries, and they were great.. recognized that nothing was going to stop our group of 5-10 people from being heard in a crowd of thousands, and cheered alongside us in good spirits (the best examples of this were the women's gold medal soccer match against Brazil.. haha and the men's Gold Medal Tai Kwon Do match; Steven Lopez did Bruce Lee.. noises.. before and after every move.. we were sitting in the front row and he acknowledged my fist-pump after he won the match with one of his own).
Best memory of another country cheering with us was the Russians and Australians who did so at the soccer match I mentioned above.. our little group of 8 turned into a mob of about 90, with them doing all of their country's sports chants/etc, and us taking part. It rocked.
But.. yeah... booing shouldn't be going on at the Olympics. Everyone shows up there as a sign of global unity/community.. obviously some teams/countries are less liked than others, but those athletes work their @sses off to get there.
.. and Hell no, I'm not saying Americans don't boo at the Olympics, I just wasn't seeing it take place, and we weren't doing it.