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Over the weekend, the ever-vigilant Urbanturf spotted an odd listing in Redfin: 1600 Pennsylvania Avenue, a.k.a. the White House. An obvious glitch, but eye-catching enough to end up on Gawker and Slashdot. Redfin swiftly explained itself: The site automatically pulls listings from a number of sites, including ones that feature properties for sale by owner. This one came from Owners.com via Oodle.

Here’s the thing: Anybody can post a listing for any house on Owners.com. In fact, I just did it for my own group home in Columbia Heights, which I do not in fact own. So, if Redfin just sweeps up all these FSBO listings, what’s to prevent me from trying to sell the Naval Observatory, or the National Cathedral? These kinds of real estate aggregators may be more closely policed than Craigslist, but there’s no way for them to catch everything.

The prankster who listed President Obama’s abode, however, clearly didn’t do their research—the asking price of $10 million is way low. Last year, Zillow.com assessed the place at over $308 million, based on its 132 rooms, 55,000 sq ft, 18 acres, 16 family-guest rooms, three kitchens, three elevators, 28 fireplaces, and one underground bunker. So, lesson for those seeking to game the system: Know the market!