The FCI standard is different than the ACK standard
It states:
Tail Undocked: Plenty of hair, darker blue in colour than rest of body, especially at end of tail. Carried a little higher than level of back. As straight as
possible. Length to give a well balanced appearance.
Docking is also illegal in many European countries.
YORKSHIRE TERRIER BREEDERS - Yorkie show and puppy news from February 2012
Here you can see most of them with undocked tails.