Our man inside the ropes on caddie camera control, a rare treat for twitchers and feline fun.
Caddies are much more than bag carrier, yardage measurer and putt reader - they're there to anticipate problems before they happen.
We all know that Tiger Woods' bagman Steve Williams can often do this in a brusque manner with potentially noisy fans and photographers in his sights.
Bones struggles to make himself heard above all the racket
One accredited snapper received a verbal volley on the range before the tournament began for having the temerity to click on the Woods follow-through.
I was very impressed by Phil Mickelson's caddie Jim "Bones" McKay during the second round.
Massive galleries were watching his man, Woods and Geoff Ogilvy. As the players arrived on the third green "Bones" surveyed the sea of spectators encircling the putting surface and saw something he didn't like.
"Marshall, marshall," he called over. "A guy there, right next to the guy in the red shirt, he's got a camera. Could you deal with it please?"
The steward made the necessary confiscation and the problem was sorted out with the minimum of fuss.
Mickelson later commented that the fans here have been fantastic, adding that he'd had real problems at the Open at Hoylake because of the number of fans using mobile phone cameras.
The R&A is considering how to deal with this issue at Carnoustie next year and a ban on mobiles has not been ruled out.
There's nothing any caddie can do about the biggest distraction here. Medinah is on the flight path into Chicago's O'Hare airport, one of the biggest airline hubs in the US.
Jets pass over every couple of minutes and sometimes look low enough to have to worry about the blimps used for overhead shots by the television broadcasters.
Furthermore, the Chicago Air and Water Show coincides with third-round day - surely not even Steve Williams could hear a camera click amid such a din, could he?
Joey Sindelar's albatross-two at the 537-yard par-five 5th was only the third sighting of this rare golfing bird at a USPGA.
The American holed a three-wood from 241 yards and it was the first albatross (or double-eagle as they call it on this side of the Atlantic) since Gary Evans accomplished the feat at the 2004 Open at Royal Troon.
American veteran Sindelar holed out from 241 yards at the par-five 5th
Five Live commentator and Troon member Andrew Cotter remembers Evans' glorious moment vividly. "It came on the 4th, the one hole where I've had an albatross - a drive and a four-iron and..." (yes, that's enough Andrew, thanks)
Previous albatrosses at the USPGA came from Darrell Kestner at the Inverness Club in Ohio in 1993 and Per-Ulrik Johansson at Riviera in 1995.
That should help comperes of the next golf club quiz!
This column championed the cause of unknown Charles Warren before the tournament began, on the strength of him coming into the field as the ninth reserve, just as John Daly did en route to triumphing in 1991.
Maybe I should have pinpointed another alternate, because Billy Andrade was sharing the halfway lead having come into the field only when Steve Elkington withdrew.
A top-two finish here would earn Andrade a Ryder Cup place
Andrade got the call on Tuesday. "The hardest part was getting here," he said.
Daniel Chopra is another reserve to make it into the field and prosper. He was only three off the lead at halfway.
BIG CAT SAFARI
This USPGA also has a distinctly feline feel.
Luke Donald attracts regular shouts of "Go Wildcats", the nickname of teams from the local Northwestern University where he was once their star golf pupil.
And, of course, a chap by the name of Tiger is doing OK as well.
Several British golf journalists were looking forward to a musical treat following the third round after a colleague spotted a Counting Crows concert in the vicinity.
At least he thought it was close and tickets were purchased. Yesterday he went into a search-engine for directions. Guess what? They involved an airport.
Springfield may be in Illinois but it's nowhere near Chicago!
A Bruce Springsteen tribute band (very good reviews says our ever optimistic music man) will have to suffice instead.