That's not uncommon, but the best ones are very forthcoming. Anymore I won't deal with anybody who won't provide a contract.
On the other hand, a lot of people expect hunting to be 100% guaranteed. I was on a hunt in Alaska a couple of years ago with a bear outfitter (very honest, and a long time in the business) who was reamed out by a client who evidently thought he was buying a high-fence deer hunt, with every night spent in a fancy lodge 15 minutes from heated blinds. The client didn't like living in a backpacking tent and not having his choice of giant bears within 2-3 days. Not so oddly, the only "outfitted" hunt the client had ever been on before was a high-fence deer shoot. So it works both ways.
The booking agent I've used the most is the one that got me started buying travel insurance. As he put it, "I offer a high-risk service during a specific period. If you can't make it because your father dies, then why should I refund your money? I'm sure you father was a great guy, but I didn't know him, and you signed the contract with me."
I know booking agents and outfitters are already paying out the nose for insurance, just in case somebody gets their toes stepped on by a horse or gets food poisoning from camp food. But if they became totally liable for YOU not being able to make it, or the outfitter dying of a heart attack, then their charges would go up enormously.
Trip insurance is cheap. For a $10,000 hunt it runs a few hundred bucks, exactly how much depending what you want covered, whether medivac helicopters or non-refundable plane tickets. You can buy it for any kind of trip, including a beach vacation in Hawaii.
