The case for Pro-Am tournaments
As Tony G said in the Coin Rivet Invitational "if you are a wolf, you have to look after us bunnies".

The Coin Rivet Invitational was lots of fun to watch and appears to prove that the Pro-Am format is a winner. 131 entries (90 uniques) is a staggering number to get for a $200,000 buy-in event and the atmosphere in the field was brilliant.
Professionals needed an invite from a recreational player to attend. The 'VIP' players all played together on Day 1 and the professionals all did the same. The two player pools were then brought together for Day 2 and beyond. Re-entries were capped at one.
For the recreational players they got to spend a whole day not worrying about being outclassed by an elite player, for the professionals it ensured an overall larger density of amateur players. It also meant that expected cheats were locked out of the game.
I suspect what happened behind the scenes was that the amateur players got to share a piece of the professional they invited too. It might have even been the case that the professional bought a piece of them to guarantee an invite. If so, it is a good way of redistributing the prize pool back to the amateurs.
Only two VIPs made the final table but there was an equal number of amateurs that made the money overall.
If you are a wolf, look after the bunnies
If nothing else this event has shown that there is an awareness among recreational players that the deck is stacked against them in these events. I think it benefits all parties to make occasional interventions to reduce pro edge, just like cash game professionals will straddle to introduce more gambling to the game. Being forced to play Day 1 with just professionals is a huge concession to make, but that meaning there are more amateurs in the field is an easy trade off.
Tony G was making this point repeatedly at the tables during the event. “If you are the wolf, you have to look after us bunnies” he kept telling the players.
It would be hard to replicate an event like this with an open field. In the UK we have a tour called APAT where it was only supposed to be open to non professionals, but that became very hard to police, so they are now just open events with an amateur player sentiment. Perhaps you could do something like drawing players with a Hendon Mob ranking below a certain amount together, but there are edge cases where pros would fit into that category.
The nearest open event you can compare this one to is the PSPC, which sees over 300, mostly amateur, players who won their buy-in for free. This attracted hoards of professionals and the density of amateur players made it worth the professionals time.
You can’t always have events where the recs get to play for free and you also cannot vet every player to ensure an equal number of professionals to recreationals. What these events show is that if you make some sort of concession to amateur players where you lose edge, you often more than make up for it by increasing the number of amateur players.
What can events do to make them more appealing to recreational players? Let us know in the comments: