For the past few months, players all over the world have been able to receive the
Eon Ticket via StreetPass. From
Friday, February 27th 2015 until Monday, March 2nd, 2015, players of
Pokémon Omega Ruby and Pokémon Alpha Sapphire that have yet to receive the Eon Ticket from another Trainer can get a serial code from Pokemon.com in order to catch either Latias or Latios in their game.
Source:
http://www.pokemon.com/us/pokemon-news/another-chance-to-get-your-ticket/