The Pokémon Company and Nintendo certainly pushed the boat out with its Eon Ticket distribution last year, with the vital item making its way around the world through StreetPass hits; they were so proud of the promotion in the UK that they even produced an infographic to show it off.
For those keen to experience Pokémon Omega Ruby & Alpha Sapphire fully it is an important item - it allows you to travel to the Southern Island and catch Latias or Latios; this is the first step in Mega evolving those 'mon to then fly and reach Mirage areas with the Soar ability. There are conceivably those, unfortunately, that will have missed out on picking this up via StreetPass, so The Pokémon Company is going to run a serial code promotion to resolve the issue; the code will be issued on the official website between 27th February and 2nd March, so there's not long to wait.
Do you still need an Eon ticket? If so, this'll be your chance, and we'll be sure to share the code once it's issued.