The recruiters you will be meeting with at a job fair are seldom the actual Hiring Managers. They are usually Human Resources (HR) recruiters who make their living as professional screeners. Their job is to weed out the undesirables so that Hiring Managers can spend "quality time" with the candidates that are on target for their needs.
However, some employers will have a Hiring Manager attend along with the HR Recruiter. This is especially true for smaller to medium-sized employers.
Consider the other side of the desk at the job fair: One hundred plus new faces in six to eight hours. Who would you remember?
You need to have a different focus for HR Recruiters than you would for Hiring Managers. Recruiters are typically looking to screen you out, not qualify you in. Your objective should be to show that not only do you have all the necessary basic requirements, you are also an appropriate candidate for their work environment. Consider their focus. Whenever they make a recommendation for further action, they are putting their "stamp of approval" on the person. The last thing they want is for the Hiring Manager to come back to them and say, "Why did you give your recommendation for that person?" They want assurance that company resources will not be wasted in taking the next step with you. Ideally, they should be able to visualize you as someone who could eventually become "part of the team."
Although recruiter styles vary, you can usually get a good feel for a Recruiter at a job fair by two very observable features:
Is the above always the case? Obviously not. These are general observations I have made over the years from going to myriad job fairs and sizing up the competition. You will find about an 80 percent positive correlation (meaning that I'm wrong a solid 20 percent of the time) in the observations above. Another observation is that fully 90 percent of government recruiters sit behind the table with no smile. Definitely weird. It's like they are all cast from the same mold. Must be government regulation at its strangest.