The benefits of commingling across jurisdictions may seem mostly theoretical much of the time, with estimates of potential revenues trailing enough zeros to fill up the unsold seats at next month's Bledisloe Cup match at Hong Kong Stadium. But there is nothing like the reality of actual racing and betting in a high-profile event to put that potential into some perspective.
Sunday's Centaur Stakes proposition in a purely local pool was almost a flip of the coin job backing Green Birdie, with 31 per cent of the win bets on the Hong Kong representative, and players unsure what to do once they go past the first three picks, which held 60 per cent of the money. Take the shorts or stand out, and many elected for the latter. Despite Hong Kong's participation, the hold was a relatively disappointing HK$12.76 million.
Compare it with HK$20.2 million for the last Japan Cup as a one-off simulcast during a race day and without a Hong Kong-trained runner.
Had punters had the opportunity to bet into pools commingled with the Japanese home pool, things would have been somewhat different as Green Birdie was second choice in the betting there at 6.2.
Hong Kong punters would have flooded to back their hero at those odds in a Japanese win pool holding HK$9.66 million at current exchange rates.
Things would have been even better in other pools, as win betting is the least popular pool in Japan, where the total hold on the race was HK$359 million in our money.
It was an echo of the day that Silent Witness ran in the Yasuda Kinen at odds of six or seven to one in Japan, but punters in Hong Kong were forced to take the usual short prices about their champion.
The arbitrage across the borders, created by the traditional hometown biases, generates new turnover. As much as Green Birdie deserved to be favourite for the Centaur, in our opinion, he was no 2.6 chance and therefore an unattractive bet.
But 6.2? That's a different matter.
Now, you might say that it's all very well for Hong Kong punters to be betting into pools in Japan, where the major beneficiary will be Japanese authorities, but it's a two-way street.
Come international time, punters in Tokyo or Osaka would love to be plonking their yen onto their own stars doing battle at Sha Tin at odds they can't quite believe and, among 127 million people, there are enough Japanese horse players to ensure the traffic on Hong Kong's side of the street would be busy indeed.
Add to that the punters from Australia, Britain, Europe, the US, Singapore and South Africa betting their local heroes here and the international day equation would be stood on its head - suddenly the international races would be the biggest holding races all year.
Such top-grade races are a tiny fraction of the calendar, of course, and commingling will be mostly conducted on Class Fours on both sides of the play.
But, since events like the Centaur or next month's Sprinters Stakes are the showcase for cross-border racing interest, it is from them that we get some inkling of what might be generated by cross-border betting, especially when Hong Kong boasts a comparatively simple, easy-to-grasp racing model, from wherever the punter is sitting.
Alas, commingling is still being pushed around the plate by the forks of bureaucrats like an unwanted Brussels sprout. It might be good for them, but they just don't like it.