Apparently some new ‘same-side guidelines’ issued by FINA last year, included in IOC rules for London posted in May. Also, the eagle-eyed reader will quickly notice that Phelps is a MacBook Pro and iPhone user :-)
Front and back of our caps… We used to be able to have front and back side with flags but for some reason there … http://t.co/Btoil7LW
— Michael Phelps (@MichaelPhelps) July 19, 2012