My company, has probably had to buy around 100 bonds in my business career as a requirement for contracts with local and state governments. Initially I had to show liquid funds for the value of the contract and personally guarantee the bond. My initial charge was around 3% if I recall correct. After proving we could complete contracts over a couple of years, we were only asked to provide company financials and the personal guarantee for the bonds. After 5-10 years, the bonds went down to around 1-1.5%.
As business grew, bonds were great for us since it eliminated a number of competitors who could not get bonded. This allowed pricing to increase 8-15% higher than a contract without bonding. This was the cost to the contracting agency to get a company where completion was guaranteed.
Agents and outfitters that are new to the business may have a difficult time getting bonded, unless they have other funds to act as collateral. If an outfitter is domiciled in Africa, probably the only way they could buy a bond in America to protect an American hunter would be to have an American bank account with funds equal to the bond/cost of the hunt, to act as collateral.
Your last sentence is probably the answer as well as the question.