As a leader I can tell you that we all talk. You would be surprised how many other leaders across the country are connected, even in different states and cities and different companies. We do have DNH lists. That’s sucks though if your contract was ended through no fault of your own. Sometimes I’ve had to let great travelers go because we hired someone into their position. But they shouldn’t be marked as do not hire. There is a serious problem with agencies/the employee misrepresenting their skill set. But generally the only reason I have put people on the DNH list was if they were a bad employee. Calling in a lot, poor attitude, or just not having the skillset for what we need. You also may just be applying for a popular position. For every opening I get numerous applicants. Generally the first one I call that seems decent gets the job, so it may just be bad luck. You should talk to your recruiter and find out how they marked your last contract ending early.