In both the movie and the novel, a Bo hostage guaranteed Michael's safety when he met with Sol and Mac. The novel says that, in addition, Felix Bo enabled Michael's freedom from prosecution for the two murders when the eturned by confessing to the murders.. Novel also says the Bo's supplied hostages for all the families attending the Commission meeting.
As Lou said: hell of a way to make a living. But, the Bo's made a hell of a good sidestory, and added some Sicilian "color."
Incidentally, there was a real-life Felix Bocchicchio. He had a rap sheet as long as your arm and was in the boxing racket with Frankie (Mr. Gray") Carbo.

very lucrative too They get a hefty fee and as I remember, no Bocchicchio hostage was ever harmed

The novel states that "...since the Bochicchios were so primitive, they never let anything, any kind of punishment, stand in their way of vengeance. They would give up their own lives and there was no protection against them if they were betrayed." I inferred from that comment that Bo hostages must have been killed, and the Bo's wrought vengeance, for them to have earned that reputation.

Don't know Turnbull while good point they must have already earned their fearsome reputation

Otherwise no one is going to trust their lives with small potatoes Bochicchio hostages and more importantly for them to even start up this lucrative but hell of a way to make a living business

I think that is exactly what Turnbull is saying; they earned their fearsome reputation.

Anyway, on a slightly different note, there is a nice little counterpoint between the movie and the novel concerning the Bocchicchio's.
From the movie when Clemenza is schooling Mike about the Sollozzo hit:

CLEMENZA
All right, you shot 'em both...now what do you do?

MICHAEL
Sit down, finish my dinner...

CLEMENZA
Come on kid, don't fool around...


In the novel, specifically the section about the Bocchicchio clan and their history:

In any case, Felix Bocchicchio was released from prison after serving three years, went home and kissed his wife and three children and lived peacefully
for a year, and then showed that he was of the Bocchicchio clan after all. Without any attempt to conceal his guilt, he procured a weapon, a pistol, and
shot his lawyer friend to death. He then searched out the two businessmen and calmly shot them both through the head as they came out of a luncheonette.
He left the bodies lying in the street and went into the luncheonette and ordered a cup of coffee which he drank while he waited for the police to come and arrest him.

In the movie,while the Corleones are waiting to send Michael to the Sol hit,there is a mention of the "negotiator" playing pinochle with Clems men,amd that until Mike comes back safe and sound,he keeps playing cards.
I wonder if Coppola used that phrasing instead of 'hostage' to avoid going into an explanation of the Bo's. I think by this time in the production, only stuff really critical to the story was going to be included.

That's a nice catch!

The book does use "negotiator" as well as "hostage." It would sound pretty odd to say the hostage is happy, they're letting him win.

When he was annotating the novel, Coppola just crossed out pages related to the Boccicchio. It could be that he didn't even process that the Sollozzo hostage was a Bocchicchio.

Sure thing the Bochicchios “fearsome reputation” they would “wrought vengeance” no matter what, seems to me “they must have already earned” before starting up their negotiator / hostage business which guarantees, the family they are being held hostage for, will be safe or else....

I am confused! So who hires these negotiator / hostage?

The one playin' pinochle, at Clemenza's place, presumably for Michael's safe return was hired by Sollozzo or the Corleones

He was hired by Sollozzo, in an agreement made with the Bocchicchio Family. If Michael was harmed during the meeting, the Corleones would kill the hostage. The Boccicchio would blame Sollozzo for loss of their kinsman, and seek revenge against him.

Thanks Pete So that's why the Bocchicchios get their fee paid in advance!

There was no hostage for Sollozzo because civilian Michael was no threat

As a matter of interest, if a meeting is arranged, say, between two warring families, do they hire hostages, for -
1. each other or
2. themselves

The Bo familymade for one of best side stories in the novel, but it was pure fiction.

I've seen an interview where Puzo said he did some research into Sicilian mafia. I've always wondered if the Bocchicchio reflected that in some way.

One issue with the Bocchicchio narrative is that at the start of the novel everyone's been at peace for ten years. Bad time for professional hostages.

!!Puzo slipped in the pure fiction of the Bo family, into his story of a fictional Mafia family, headed by Vito Corleone, The Godfather!!
That was no fiction!

True Pete Puzo's research probably reflected that aspects in some way.

I think, from what I remember, they had a garbage hauling business during the peace time

I reckon it is all about guaranteeing the safety of their Guest. I don't think they hire hostages for themselves

So depending on the circumstances, I reckon, Vito would hire the hostage for the other family because he is the formidable, bigger threat same as Sollozzo did for civilian Michael

backfired plans he was not forced into as we debated, in Was Michael a tragic figure? thread,

Kay
Michael seeking Kay out, his horror of a wife
Bet hypocrite Kay never told Anthony about his unborn brother she murdered

Frankie Pentangeli
It was indeed unbecoming of a Don
1. Michael “undercut Pentangeli through his support of the Rosato Brothers” against his own man
2. Michael gave his loyalty to a Jew [Roth] before his own blood
3. Michael asked Pentangeli to lay down - settle these troubles - to the Rosato Brothers who spit right in Pentangeli's face
4. Michael threw Pentangeli [good old man -- who was loyal to Vito, Michael's father and to Michael, for years] under the bus
5. then abandonment of his 'dead' capo's family

Fredo
no excuse whatsoever for “Fredo’s betrayal;” for something in it for me -- on my own, the Donship
Nevertheless Michael could have spared Fredo

Mary
Michael surrounded by his family, was parading himself and his family in public, so out in the open even at the steps of the Opera house in Sicily, in the night, in full view of anyone lurking knowing Mosca, the assassin who had never failed thus far, was contracted to murder him and that Mosca had already murdered Don Tommasino Go figure!