So, an undergrad comes in for an interview for an FT or SA position.
I would think that anyone that wants to get into IBD or Finance in general will have done extensive research on how to break in, and will therefore have read WSO threads on the matter, M&I etc.
If I saw someone who has obviously not read up on how they should dress, and they're wearing square toe shoes and the works, I would see it as someone who either doesn't care enough to make sure nothing is left to chance, or someone who thinks he's too good to dress the way bankers want him to dress, which would tell me that this person obviously won't be OK taking shit from VPs and doing the "unimportant" grunt work, because he fancies himself better than that.
The reason I'm asking is because today at the careers fair people were truly dressed horribly. Loads of people with black blasers and grey trousers, ugly ass shoes etc.
Of course, many people don't have money to dish out, and I wouldn't ding someone because his get up looks cheap. But you can do cheap and still look presentable.