My dog has an interesting (okay, disgusting!) habit of rolling in the smelliest stuff she can find when we go on walks. Everything that I've read about dogs - and this probably includes fiction - explains her behavior as "the dog is hiding her scent."
I know it seems odd that my dog rolling in smelly stuff should remind me of a post on Evolgen (Lab coats & Gloves), but he did make me wonder if he might have missed a reasons for some people dressing as they do. RPM looks at this issue from a very logical standpoint. Since he works in a lab, he thinks that the people wearing in lab coats in the cafeteria might work in the lab also, and therefore, be covered with nasty goo.
But things might not always be what they seem.
I think some of those coffee shop lab coats never go near a lab bench (or a sick person). Those misled fashion statements, could actually be PIs (PI = principal investigator, usually a professor or assistant professor). Since they don't do lab work anymore, they don't stop to consider that there might be nasty chemicals or microbes on their clothing. And, often there aren't, since they only wear lab coats for public appearances.
We had a biochemistry professor at my university who only wore a lab coat for two kinds of occasions: photo opportunities or teaching. If the medical school needed a picture for an annual report, there he'd be staring at our gels, with a photographer close at hand. For his teaching responsibilities, he was a bit more selective. He always wore a lab coat when he lectured to medical students, but he never wore a lab coat for our graduate biochemistry class.
I wonder now, if he wasn't trying the same strategy as my dog.
Blend in with the crowd, avoid being noticed.