Yup~ I have a sister-in-law that does this, but swears she's not. Very passive-aggressive.
Our niece was giving her non-dub mother a surprise birthday party. Many people were coming driving 3 hours to get there. Sure enough, her witness sister had to call her and just let it "slip" about the party. She has done this other times, too. When called on it, she just shrugs. Her attitude that can do nothing wrong is infuriating to the rest of us.