Wow, schools actually have dress codes? Sucks to go to that school. At LIU, the only time I've ever worn a lab coat is in microbiology lab.
The pharmacy students just wear a lab coat to the labs, but I've never heard of this business casual shenanigans. Unless the person is a prick, most people generally wear a hoodie and jeans.
And for the lab coat, I just wear a t-shirt and jeans underneath it. Health-care is not a business and it shouldn't be run like one.
Back to the point about scrubs, I love them, they are so comfortable. I just hate it when people wear scrubs outside of work. I mean, just wear your t-shirt and jeans until you get to the hospital, take a shower there and change into your scrubs, instead of picking up the millions of microbes on the buses and trains.