I've had this problem in reverse. MC has repeatedly flagged local/regional purchases as potentially fraudulent, but we have never had a single international purchase questioned. Can anyone explain why this is happening?

Maybe I need to call to tell them to tell them when I plan to stay home?
Here's the details. Two years ago my husband and I applied for and received an AA Citibank MC. Since then he and/or I have used that card all over the world. (Asia, Australia, Central and South America, the Middle East, several European countries, Canada and Mexico). We have never informed the cc about our travel plans. Sometimes we travel together and sometimes we are on opposite sides of the world, but we have never had a single foreign purchase questioned.
Yet on at least three separate occasions our card has been flagged because of *local* purchases. The parking fee at DFW has been questioned twice. Citi MC called to see why someone who lives in Oklahoma would have a parking charge in Texas, even though this has been a regularly recurring charge for the past two years (average 4-5 per month between the two of us). If parking out-of-state is truly an alert to fraud, why did the computer wait 15 months before it *caught* this?
Another time it was a fuel charge in OKC that occured the same time as a fuel charge in Texas that caused concern. But I don't understand why it seemed suspicious for two card holders to charge at two different gas stations located within 100 miles of the home address, when simultaneous charges on different continents have never raised an eyebrow.
If someone can make sense of this, I would love an explanation.