Depends. When the sponsor/host of a job fair says that the dress code is "business casual" when they get up there and speak before the job fair even begins, as well as states that the company's recruiters that showed up (the most desired "legacy", the most desired "LCC", and most desired freight company) like it that way as well as dressed business casual themselves for the relaxed environment it creates for the 30 seconds of "face time" you'll get, what do you do?

To take it a step further, there's a couple coveted shops out there interviewing pilots and the interview directions state the dress code is business casual. The guys that show up wearing the standard issue interview uniform stand out, and NOT in a good way. Cant follow directions = NOT the kind of pilot they're looking for.