If a woman flashing a bit of breast while feeding her child is not indecent exposure, I don't see why the sight of a willy that was clearly an accident would make people run and scream bloody murder.

I think the story about the parade has the right of it- as long as cop doesn't think you're doing it on purpose or to make people uncomfortable, you're in the clear. I hate to say it, but here in America we've heard so many jokes and seen so many scenarios where a men goes off kilter from a breeze, it would be about the same shock value as seeing a man in a kilt in the first place. Maybe less so- we're prepared to see the blue ribbon winner under the kilt, it's the kilt that's the surprise in the first place!