Accidental ear flippage, often a result of rolling around like a goddamn maniac, is almost exclusively reserved for dogs with floppy ears, much like the one pictured. Occasionally a cat or a pointy-eared dog will have their ear flipped, but it's a rare citing, like a bald eagle or a sober fraternity.
But a human having his or her ear flipped inside out isn't just rare, it's impossible. And if it does happen, seek medical attention immediately...or make a video and put it online. The only real advantage to this ear flipping ability dogs have is that it doubles their "Holy Shit You Guys, That's So Fucking Adorable" factor (a factor that is already five times higher than a human's, on average), making them more likeable than us without any effort on their part.
(flickr photo Someone Should Tell Him by email@example.com; http://www.flickr.com/photos/auntylaurie/2086698729/)