Just why do Americans find it so hard to understand that the royals don't like to be touched?!
Do they not recall the appalling ramifications of the infamous moment when Michelle Obama put her arm around the Queen in 2009?
The shockwaves of that incident are still being felt in some dustier corners of the realm.
There were not just one, not two but THREE breaches of protocol last night.
The first was by someone who really should know better, Hilary Clinton. She actually petted Kate's arm when she met her at a reception last night. Then Jay-Z casually touched Prince William on the arm.
But the worst by a long way was when a very sweaty post-match LeBron James swung his whole arm round Kate's shoulder for a photocall. She looked worried.
Honestly, guys, you'll be lucky if they ever come back.
The informal ban on touching royals stems from a time when monarchs were accorded an almost divine status and had to be treated accordingly.