The law in the State of Washington:

"A person is guilty of indecent exposure if he or she intentionally makes any open and obscene exposure of his or her person or the person of another knowing that such conduct is likely to cause reasonable affront or alarm. The act of breastfeeding or expressing breast milk is not indecent exposure."

The key phrases here are "intentionally," "Knowing" and "cause reasonable affront or alarm."

Let me present two possible scenarios:

1. While walking down a public street, a stray gust of wind blows a man's kilt, briefly revealing Scotland's Pride to any who happen to be looking at his crotch at that exact second.

2. While standing in a playground, supervising a dozen or so 9-year-old girl scouts on the joys of kite flying, a stray gust of wind blow a man's kilt, revealing the same.

In both scenarios there was no "intent" to make an "open and obscene exposure." However in the second scenario, it is reasonable to assume that such and exposure would be possible - even likely.

In the first scenario, there may be "affront or alarm," but not necessarily an "unreasonable" amount.

In the second scenario it is likely that the incident would cause a VERY unreasonable amount of "affront or alarm." In fact, though the kilt wearer did not directly expose himself by his own actions, a "reasonable person" would expect that an exposure in that circumstance is likely and exceptionally alarming to those who witness the exposure.

Laws vary by jurisdiction, but I would expect something similar on most books.

The bottom line is common sense. If it's a legitimate accident, it's not a problem. If it's an accident where you really should have known better, it might be an issue.