Mario with Lasers
Unfazeable
To be fair, Shinies were supposed to be astronomically rare so i think GF are making it difficult for some to be shiny because they feel shinies are obtained too easily (but then they made the pokeradar) or maybe they don't like the idea of the legends being shiny anymore as they are one of a kind.
Also it's possible that the creators want to encourage people to play the games the way they were originally meant without people spending hours/days/months/years sitting at a standalone and SRing.
I'm not bothered about the checks atall. It means i have less to SR for =P since i am doing a shiny dragon hunt i don't have to worry about Reshiram and Zekrom.
People still SR for IVs/Natures. And only Victini/Resh/Zek can't be shiny, if they wanted no more shiny legendaries, they would have done the same to the other ones...