You do not expect to hear hundreds of emergency vehicle sirens approaching a White House function.
But sirens they were - and they were incredibly necessary.
For Jennifer Lopez, who had ill-advisedly crammed her generous rear end into a Victoria Beckham designed party frock had not reckoned with the poor quality, Korean sweat-shop quality.
The double ended metal zippers - so much a feature of Beckham design - were not up to the task and failed catastrophically.
2000 slivers of sharp-edged high- tensile steel in the form of zipper teeth scythed through the room as J-Lo bent forward to accept a hot dog from President Obama.
"The noise was shattering" says First Lady Michelle Obama "and I just covered my ears and screamed. It was like machine gun fire".
Victoria Beckham's agent has issued a statement:
"I am devastated by this dress failure. The zipper manufacturer is now known to have al Q'aeda connections so this attack was an attempt to assassinate President Obama and me. The use of Improvised Exploding Dresses (IED) is a new terrorist threat".
President Obama has assembled a task force that is to search Korea for Weapons of Mass Dressmaking and says he will remove the evil regime and replace it with McDonalds Democracy.
The fate of J-Lo's booty is not known.