NEW YORK — Sadie the Scottish terrier won America's top dog show Tuesday night, and that was pretty predictable. What happened moments before she took the title at Westminster was far more startling. Two women walked into the center ring at Madison Square Garden and held up signs that said "Mutts Rule" and "Breeders Kill Shelter Dogs' Chances," the latter a slogan popularized by People for the Ethical Treatment of Animals. The crowd of 15,000 gasped at the PETA-inspired protest, then booed the women and cheered as security ushered them away without incident.