This is just my feeling about this and not anything "official," but I get the feeling that this is the end result of too many guys taking the job and then going to UAL, AA, SWA, when they get a job offer from them.
Traditionally, when you got called for an interview, you were basically hired, it was your job to lose. However, Delta only had a small window to get to know the applicant. By doing it this way, not only do they get more time with the applicant, the applicant gets more time with the company. That way, it cuts down on the lateral movers. For every spot an applicant takes, just to move on a few months later, is one less spot that someone who truly wants to work at Delta can have. Not to mention the cost of having to replace that individual.
Again, just my thoughts on this. I think it's a great idea. It's kinda like the old CP pre interview interviews. I want us to only hire those that really want to be here, not guys that are just looking for a paycheck until some other airline calls them.
This is what I think might be going on.
It's really more about cost and career fair fatigue.
Hitting an big national, there's probably as little as $25K up to $100K in sponsorship fees and booth rental. Then there are things like $200 extension cord rentals, then you've got to pay travel time plus flight pay for 15 to 20 recruiters, meals, lodging, just going to a career fair run a tab of $200K if you're not careful as a pilot recruitment department.
Then there are the applicants. Days off, high costs, hotels, registration fees, standing around in line, confusion over "is this a fast pass?" "a reservation?" "standbys?" "walkups?" and you've got sometimes thousands of applicants who have dropped anywhere from $300 to $1000 depending on the organizer.
And the internet gossip is that you get "points for the number of job fairs you go to"
WHICH IS NOT TRUE or if you went to one, but not the other you're "not showing interest"
WHICH IS NOT TRUE, and so there are applicants that spend crap tons of money on the job fair circuit, paying tons of money on consulting fees, "bootcamps", application prep, etc and you have some people dropping the amount of cash to purchase a used car.
So there has been a listening campaign where they listen to the concerns of the applicant, the recruiter, real people giving real perspectives and the result is, that they want to run one on campus. It might work or it might not.
But this isn't the typical situation where the applicant gets the day off, jumpseats to Fresno. Drops $100 on a rental car, $400 in hotel fees over the span of a couple days, $350 in registration fees, $100 for a fast pass, THEN he stands in line for four hours in order to have someone say "Well, thanks for coming, we require 1000 hrs turbine fixed wing".
I bet they've done a lot of watching and listening to the concerns of the people involved.