I would most definitely be good to see the flag IF the user wants us to. Let's not forget this is an opinion website, and some countries have, erm, stricter policies regarding free speech on internet. Ex: I wouldn't want a cool user to get in trouble because he is talking against his regime.
But it would be very interesting to know where people are from, it adds an insight to their opinion. It could also be useful for graphs, comparing what people vote for according to their location. Ex: An Australian citizen might not have the same views as a US citizen on gun control.