I had some experience as a Grey Group "coordinator" and bailed (I think) about the time Paul transitioned to Alias.
There are certainly benefits to the "broker" model for all involved when it works well. For whatever reason, it seems hard to make it run well.
The coordinator gets a free class slot, maybe two, for their trouble.
The instructor gets to just arrive and teach, rather than deal with paperwork (not exactly a strong point, or something they want to be bothered with, for a "tier one" gun).
The student gets a single POC and fee.
The range gets exposure to new students as potential members.
instead what happens (in my experience)
The coordinator gets nowhere near enough communication from either the broker or the instructor. I asked every single instructor for an equipment list and every single one said "we'll deal with whatever the range has" only to complain later on about the range equipment. Not wanting to do your own admin is not the same thing as not doing a minimal amount to properly prepare. I saw this as a failing of both the broker and the instructor. Grey Group typically sent along a box of some amount of supplies but it was often wrong, missing things, etc. and clearly indicated that the person on the shipping end hadn't a clue and was trying to save pennies where they didn't matter.
The instructor doesn't know what he's walking into, and has to deal with things he should have had to. He also has to wait to get paid. and has no control over who shows up. That last bit turned out to be a problem for me and for them in every single class I took. There was always at least one full choad that should have been filtered out by GG but who was there because they had money.
the student gets mixed messages, often still gets hit with range fees on arrival, and may have trouble dealing with canceled or rescheduled classes, mostly due to bad scheduling on the part of the broker (like conflicting with themselves or other classes at the same range or in the same market).
The range gets hosed on fees, beat up and trashed, and blamed for everything by all of the other three parties.