At least the general consensus is to care about it. My dad was raised, with 7 siblings, by a Marine, who served in WWII. He taught me to be responsible, hardworking and dependable. But he knows nothing about the ins and outs of the airlines. I see that in others, also. But you do get the clueless folks, who make you wonder how they managed to figure out how to apply in the first place. I've interviewed impromptu in scrubby attire and gotten the job enough times to scoff at worrying about what color suit to wear. If there's a special style that I need to know about and it's not included in the invitation, then it's not my fault that I'm not wearing what they want and that's probably not the only reason they won't give me the job. I once interviewed twice for the same job and was given essentially the same interview (regional airline). I interviewed the 1st time in August of 2005 and the second time in November of 2006. There were 4 of us fighting for 2 jobs the 1st time. The feedback they gave my sponsor (he walked my résumé in both times- brave man) was that my instrument knowledge was "weak". I remember the question in the face to face that they scrutinized the most. They asked it again on the 2nd interview and I answered it the same because I was confident I knew the answer. I got hired the 2nd time.
I'm almost certain the biggest factors, BEFORE you set foot in the door, are need and outside influence (people pulling for you). AFTER you walk in the door it's where you are coming from (your experience) and how your confidence represents your experience, which is what they are primarily concerned with. If you don't look like a scrub and you followed any attire instructions they gave you, it's not the tie that gets you hired.