Just to elaborate a bit more on agencies and their policies, I will give you the few experiences that I have had.
1. VOR Holdings. I contacted them about 2 years and 5 months ago. After first contact, they send me a contract, obligating me to use them, for all airlines in China. I refused and told them I would sign for one. I got a real bad feeling about these guys, so I bailed soon after. Never could get an honest answer out of them. I have not seen one of their contracts, but what i have heard reminds me of the contract I will describe below.
2. Rishworth. Once again after first contact they send me a mini-contract obligating me to use them for the airline in quesiton. I get a screening date, and they make me sign another mini-contract, obligating me to accept the job after screening, or pay thousands of dollars. I ask to see the contract with the airline beforehand, but they said that is not their policy. At this point I am bound to them for this airline, so I continue the process. I pass the screening, and they send me the working contract. Holy @#$$%% batman, you wouldn't believe the contract, and if I refuse, I owe them thousands of USD. The contract is the worst rubbish I have ever seen. Obligates me to everything, and Rishworth to nothing. It even states that in the event that we have a disagreement or they violate any part of the contract, I cannot hold them legally liable!!!! If they break one clause of the contract, the rest of the contract remains in effect!!!! And get this, I can't allow ANYONE to see the contract, which I assume means a lawyer!!!!
Worst rubbish I have ever seen, and I was stupid enough to sign it.
I have heard VOR Holdings contracts are quite similar.
My Parc contract, in contrast, is a basic contract between two business entities. Each has obligations, and each has an "out". Very well done, I wanted a to have a couple things clarified in the contract, so they changed the wording to what I requested. No problem.
That has been my experience in dealing with 3 different agencies.