Everybody understands that the only real way to prove you've got what it takes to be considered among the best at anything is to take on those who already have attained that status.
But what if the best poker players in the world aren't all here at the Rio?
I'm not going to suggest for one minute that the players clashing daily on the felt inside the Amazon Room aren't some of the cream of the crop.
In fact, with big names like Tom Dwan and a host of others, the fields often include much of the top of the poker food chain.
But a player I ran into on the rail the other day reminded me that not all the best and brightest are here.
Canadian Mike "Timex" McDonald has been ripping through the world of online poker since he was way too young to mention. This winter when he turned 18 and found he was old enough to play on the European Poker Tour, he leapt at the chance.
Still under the age of majority in Sin City, Mike made the trip down to sweat a friend by the name of Aaron Coulthard, who had made the final table of Event 2 - one of the many $1,500 No-Limit Hold'em tournaments on the schedule.
McDonald says Coulthard, also from Waterloo, Ontario, is one of the people who taught him the game, and Coulthard certainly did a fine job. But Mike is only one of a number of players deserving of at least a quick mention when the conversation rolls around to who is among the best poker players on the planet right now, but yet unable to prove it here.
Norwegian phenom Annette "Annette_15" Obrestad is another great example. Given that she's still under 21, the only WSOP bracelets Obrestad can contend for are those awarded at the same events Mike McDonald played on his 18th birthday last year, in London at the World Series of Poker Europe.
When she was given the chance in 2007, Annette certainly took it, mowing down a field of the best in the game too shocked that this little girl was making so many aggressive plays against them to figure out a way to combat it.
By winning the $10,000 Main Event at WSOPE, Obrestad grabbed £1 million and the attention of the entire poker world with it. Add a few mythical tales flying through the poker stratosphere regarding the online bankroll she'd built from scratch, and her name was suddenly being included on the roster of poker's elite.
It's not just Canadians and Europeans either who are affected by Vegas' age restrictions, as Californian Isaac "westmenloAA" Baron will also be absent from this WSOP.
Baron is consistently named the best online player on the planet, and proved he could make the successful transition to the live game with an 11th-place finish at EPT San Remo and a final table of the EPT Grand Final in Monte Carlo where he went out fourth.
But his 21st birthday is on Day 3 of this year's Main Event - much too late to join in all the fun at the Rio this time around.
These three represent an entire army of young hyperaggressive poker players with no fear who inevitably come up in any conversation about who's on top.
I understand these kids will get their chance one day, but once they do there should be a whole new crop of under-21s who are already ready for prime time taking their place.
So until they lower the age of majority in Vegas, or Hell freezes over, I consider the World Series of Poker Europe an even better test of who is the best.