The best Chrome Dev Tools feature.pic.twitter.com/7ZzWsJchW1
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Yeah I have a hot key that literally types what's in the copy buffer for this reason. It sometimes confuses autocompleters and other overly intelligent fields.
you should be able to turn it off browser wide but it should be on by default
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.