Because, otherwise it looks suspiciously as though Kourtney Kardashian,33, has raided her little sister Kim's close to steal away these leather trousers.
They look exactly like the pair that seemed surgically attached to the 31-year-old over the weekend.
They look familiar: Kourtney Kardashian stepped out in New York today wearing a pair of leather trousers that looked suspiciously like Kim's
Later, when they stepped out for dinner, they were still showcasing her famous rear, though she had changed tops.
And on the Sunday, when she arrived in LA, the trousers were there again.
Casual leather: Kim wore the favourites on Saturday afternoon as she enjoyed an intimate stroll with Kanye (in front of several dozen photographers)
Take two, take three: Kim kept the trousers on in the evening, and was wearing them the next morning
However, that wouldn't make complete sense.
Kourtney is, of course, quite pregnant, and has a sizable bump.
Bad idea: The short leather skirt didn't work on Kim's figure
Today, Kim opted for jeans, but couldn't resist a bit of leather action, which took the form of a pleated short skirt.
It was a bad idea, so hopefully she can sneak into Kourtney's room when she's distracted with Mason and nab them back.
Splash of colour: Kourtney was later seen pairing her leather trousers with a patterned kaftan-style top as she strolled in New York