Fake toes, for all you people with gross feet who wish you could wear sandalspic.twitter.com/84G4R4YAx1
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
Also: Closed toe sandals. 
Also, at least for those of us working in academia, just put on regular socks, they also work in sandals!
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.