LeBron James raised some eyebrows when meeting the Duke and Duchess of Cambridge on Monday in Brooklyn.

In exchanging gifts, the basketball star raised his athletic arm and placed it on Catherine Middleton's shoulder, a move that is regarded as a breech of etiquette.

Commoners do not touch the Royal Family, except to shake their hands when introduced.

Here was the scene:

The Telegraph

Note that Prince William doesn't seem to know where to look. Catherine keeps her grin fixed. James had just spent 34 minutes playing for the NBA's Cleveland Cavaliers in their 110-88 victory over the Brooklyn Nets. We assume he had a shower.

Reuters Having said that, breaches of the no-touching rule occur all the time with the Royals. And it's not as if James were putting a leg around Catherine's waist, as happened to her father-in-law Prince Charles in 1999 on a visit to Argentina.

Prince William's reaction (he hardly noticed) tells you a lot about the modern Royals' attitude toward etiquette. The Prince simply looked away.

"I don't think that they are as hot on etiquette as most people think they are," said Jennie Bond, the BBC's Royal correspondent for 14 years.

Times are changing, and so does the etiquette.

Many still remember Charles' encounter with the Spice Girls, when Geri Halliwell broke more than one rule by pinching his backside.

Here is how it looked. You can see the action behind Victoria Beckham, who is mugging for the camera.

Youtube

Meeting the Queen is another story, as Michelle Obama would remember from her 2009 visit to London. On that occasion, the hug between the First Lady and the monarch caused an uproar:

REUTERS/POOL

Former Prime Minister Tony Blair grabbed Her Majesty's hand on New Year's Eve of 1999/2000 in Glasgow. It's not strictly a breach of the rules. She does not appear to appreciate his common touch:

BBC Pool

And when Paul Keating, then the prime minister of Australia, met the Queen in 1993 he did not think twice about putting an arm around her back to guide her through MPs and bystanders. Keating also wanted Australia to become a republic rather than a dominion ruled by the British monarchy, so the Queen probably did not like it either.