Much like real estate agents, their best interest is to close the deal at any price. They'll make more money getting the employer a bargain and a second req.

There is a reason real estate agents homes sell for more than anyone else's -- because they know the real value of the market and have an incentive to go high when it's their own home. Recruiters are the same.

This is incorrect. It's in their interest to get as high a salary with the least effort involved.

Obviously for them, being able to close more candidates at a "high enough" salary is preferable.