My yorkie girls never have yet (knock on wood) but my pekingese Snoot seems to be gassy since he got older. He's almost 12 now
It actually cracks me up because all of a sudden I'll hear " toot" and he's soooo confused by it, hehehehe!! He just stares at his butt for a few seconds and then goes on with his normal business.
It's not very often so I never worried about it.