I figured this out at Murrayfield last Friday when I was approached by one of their supporters, who handed me his camera and asked me to take his picture, with the stadium as a backdrop. Le selfie was obviously an alien concept to the fellow.
"Merci," he said as I handed the camera back. "Mon plaisir," I replied, in that suave way I have, somehow concealing my raw fear that he might take it as an invitation to carry on the conversation in his language rather than mine.
Fortunately he switched back to English, asking if there was anything for visitors to see at the ground. Maybe an exhibition or something like that?
At this point I felt a pang of embarrassment. He was obviously a rugby nut, and here we were in the city that gave birth to the international game, in front of one of its greatest cathedrals. And I couldn't help him. In consideration of his feelings, it was only right that I replied in French. "Non," I said. "Rien."
This, though, is what I wish I could have said: "Well, it's funny you should ask, for the SRU have just opened a splendid new museum in the west stand. It was built after years of heroic and selfless campaigning by a group of dedicated individuals and it is now home to some of the greatest and most priceless artefacts in the game. It's a fascinating resource. Get yourself round there tout suite."
But I couldn't. The SRU does indeed hold an astonishing array of trophies, mementoes and documents, and that group of heroic campaigners did and does exist. In fact one of them, Mike O'Reilly, stood up at the Union's annual general meeting three years ago and delivered one of the greatest speeches that usually staid gathering has ever witnessed, supporting a motion to create a museum at Murrayfield. In measured, passionate tones he made his case superbly - and won overwhelming support.
Mike knew his stuff. For years, he had beavered away selflessly in a windowless room at the stadium, cataloguing and caring for the SRU's historic collections. If you wanted to know something, Mike was your man, but he left the Union in disgust when the cabal of accountants who ran the place at the time ordered that the material he had cherished for so long should be packed into storage boxes and moved off-site.
But at that 2011 agm he took his revenge on them quite brilliantly. The beancounters did not know what was coming when their quietly-spoken ex-archivist, now representing Orkney RFC, got up to speak. But then they probably didn't know that, in his previous life, Mike had been a senior detective, well used to dealing with the toughest nuts on Edinburgh's mean streets.
He took them apart that day, spelling out their shameful stewardship of the sport's history. "Nobody," he said at one point, "not even an accountant, can pretend that our heritage never happened." The motion, calling for the museum to be set up in the west stand on a budget of £250,000, was approved almost unanimously. "There wasn't a dry eye in the house," said Sir Moir Lockhead, who had just been that day installed as SRU chairman. "It was just brilliant."
He was right. And it would be just as brilliant if Murrayfield officials, under Lockhead's chairmanship, had bothered their collective backsides to actually do what their membership told them that day.
Oh, you'll hear the odd muttering about a working party that might be set up or a briefing paper that might be written. "Leave it with us," comes the Murrayfield message. "We know what we're doing."
Well, on the evidence of the past three years, their stultifying inertia and their monstrous disregard of an explicit instruction from their membership, they clearly do not.
The original timescale - one year - was almost certainly too tight. The £250,000 budget was almost certainly too low. But to progress the issue with the urgency of a slow-growing root vegetable shows staggering contempt for the sport as a whole. Sure, there's not a lot of spare cash lying around at Murrayfield at the moment, but the Union's non-executive directors and council board members still managed to lap up fees of just short of £200,000 last year, and you can buy an awful lot of glass cases for that sort of money.
What is lacking at Murrayfield is the will to make it happen. There is virtually no sense of tradition around Murrayfield these days, no sense of being part of a great, historic timeline, no rootedness.
If you don't know where you come from then you don't know where you are, let alone where you might be going. England coach Stuart Lancaster has hammered home that message to his players, creating a culture of respect and responsibility amongst them. Making sure they know the history behind the jerseys they wear is very much part of his philosophy. Of course, it's probably easier that the Twickenham complex includes a museum.
When I left my new French mate - I suggested the pandas across the road as an alternative attraction - I walked into the stadium itself.
On the agenda was a pre-match briefing with Scott Johnson, who had just been talking with some of the Scotland grand slam heroes of 1984 and was clearly moved by what they had to say. "It is a good story to tell," said Johnson of their accounts.
Quite, I thought. Anyone know what the French for irony might be?