It still started a really stupid trend nonetheless. Ever since then they've gotten more and more invasive with what you aren't allowed to shiny hunt for beyond the obvious mythicals. In X/Y the main trio, Kanto birds and Mewtwo couldn't be shiny, in ORAS the main trio, the cosplay Pikachu and Deoxys (I count it here since it's treated as a "regular" encounter and not tied to an event), SM the Cosmog line, the hat Pikachus, Ultra Beasts (who were unlocked in USUM) and Tapus, and then SWSH took it one retarded step further by locking out the starter you begin the game with, the G-Slowpoke that kicks off IoA and the main trio as usual.