I did this with my last job.
The only thing that was a bit irritating was the recruiter kept bugging me after I'd ditched them. It was almost comical because they called me and said something like "the school really likes you and wants to hire you, can you come in tomorrow and sign a the contract?" To which I had to reply, "Yes, well I'm aware they like me and want to hire me because I signed a contract with them 3 days ago." This got their panties in a wad and they called me several times trying to convince me to sign "their" contract. In fact, in the end, the peon who I guess was in charge of this "account" called me in tears, no doubt because she'd been told off by her boss for letting me slip through the cracks (cracks which were created largely by the peon, who sat by and allowed the principal to put his personal business card into my hands when she brought me in for an interview).
In the end though, there was nothing they could do. That's the risk you take when you're the middle man -- it benefits everyone if people can figure out a way to cut you out, so if they can do it, often they will. I told the recruiter that whatever business they had with the school, leave me out of it, because I had no obligation to this recruiter, in fact, if I'd known that I was dealing with a recruiter I probably wouldn't have even shown up for the interview. As far as I was concerned, the contract was signed, and if the recruiter felt there was some breach of protocol, then she needed to take it up with the party who was actually paying for their services. Anyhow, I told the principal that the recruiter was harassing me and he put a stop to it. Don't know if he ever paid them or not (it was supposed to be a flat fee, I know that much) but I suspect not.