Woe betide anyone in America who's not up to snuff on the Stars and Stripes. But apparently when other flags, even those of staunch allies, are the issue, anything goes.
For proof, look to the fiasco at a Pentagon lunch in honour of Ion Iliescu, the President of Romania.
The government in Bucharest has sent 800 troops to Iraq and was hailed by George Bush as a stalwart in the war against terror. Romania is due to join Nato next year.
None of that was enough to have prevented Mr Iliescu's table on Monday being adorned, not with his country's red, yellow and blue flag, but with the white, blue and red of Russia, successor to the Soviet Union, the former master of Romania.
Quite how the mistake was made is unclear. Probably some underling in the protocol department confused Romania with Russia, which follows it in an alphabetical list of the world's countries.
But the Romanian press had a field day. "Memories are coming back to haunt me," was the headline in the daily Evenimentul Zilei, above a photo of Mr Iliescu with Donald Rumsfeld, the US Defence Secretary, with the American and Russian flags between them.
The US embassy in Bucharest was contrite, talking of an "unfortunate and embarrassing mistake with no disrespect intended". The Romanians were charitable too: "Neither you nor I know all the flags of the world," a spokesman said.
All of which would be fine - except that America has slipped up before.
In 1992, the national flag of Canada was flown upside down for a World Series baseball game between the Atlanta Braves and Toronto Blue Jays.Reuse content