The rules also state any official event pokemon, which blaziken is
9.1. Standard Format
The Standard format is the standard tournament format for Play! Pokémon video game events. This
format will be used at all premier events unless specified otherwise. The Standard format for the 2014
season will use the following restrictions:
Only Pokémon X and Pokémon Y Game Cards or downloadable versions are permitted for use.
Players may use Pokémon from the Central Kalos Pokédex from #001 to #150, Coastal Kalos
Pokédex from #001 to #153, or Mountain Kalos Pokédex from #001 to #147.
Pokémon must be placed in the Battle Box.
Pokémon are allowed to Mega Evolve.
Pokémon above Level 50 are permitted, but they are auto-leveled down to 50 for the duration
of battle.
Players may use Pokémon with Hidden Abilities.
Players may use items that have been officially released via Pokémon X, Pokémon Y, the
Pokémon Global Link, or an official event or promotion.
I think it's pretty clear that Blaziken won't be allowed. The only place where it mentions event pokemon are when a pokemon learns a move from an event, or an item is distributed via an event