Now some of the rest of this little post I figure is right on and some, well, is a logical assupmtion, edjucated guess, or an out and out SWAG.
As far as the experts, they are people who are either specialists in a certain style of shooting or with a particular weapon (not necessarily both) who are appearing for a fee. The experts usually do not "teach to the test" so they are there a lot of the time just to teach how to manipulate the weapon in a way that can give the shooters the best chance. They've gotten to the point that former competitiors, especially winners are used for some specific types of shooting, and there are always a good share of exhibition and trick shooters (Jerry Michelick sp? has appeared more than once.) The credentials of the experts/coaches are given at the start of each show and I'm sure that once they got into the loop of these folks getting people to appear wasn't a problem, it is a payday after all. When it comes to some primitive weapons (how many people actuallly know how to use a spear throwing stick) I'm sure the field of experts is really small. As for the firearms my bet is that the modern arms are provided by the manufacturers for a promotional fee, all the firearms get a plug. SIG and S&W pistols for example seem to be used a lot and it wouldn't surprise me if the show didn't have a special financial arrangement with them. The old milsurps and commercial weapons are usually easy to find examples (Nagants, '03s, Winchester lever guns ect.) and since no one gets a plug on them my guess is they are mostly privately owned loaners but that's just a SWAG. What I'd like to know is where they get the machine guns and field artillery, both are now used at least once every year. Boxes of ammo showing the manufacturers name are usually displayed before each stage. In the cases where they aren't I figure the show and the manufacturer didn't come to an agreement so the ammo company dosen't get the plug.
It is supposed to be a money making proposition.