If you check out the flat flags the colors are exact, obviously the styled ones have subtle shadowing etc, and are probably out by a very small margin.
It's a set of flag icons for the web, it's not to hang off the government building.
If we did exact aspect ratios for every flag they would all be different and look shit. We tried to be as exact as possible with colors and shapes, if they don't work for you guys or are not close enough then you don't need to use them.
Not aimed directly at you, just at anyone who doesn't find them precise enough.
If you want vector flags use wikiepedias SVG flags. These are made to be pixel perfect at different sizes, something that wouldn't work if we just batched them all from vectors.
I just wish Firefox wasn't coping iOS. Slide open, 4 x 4 grid with a dock, swipe between panes. It's just sad that companies think this is the 'standard' for any phone os and stick to it. Metro gets some respect from me for taking a fresh approach, this, unfortunately doesn't.