Let's see...FA or pax drops glass (happens all the time), glass breaks into hundreds of pieces on floor (not all of which can be located/picked up), idiot in bare feet walks down glass and cuts feet. Sounds pretty clear to me. At least a double layer of socks would minimize the damage from small shards of glass. Not a scientific article, but just plain common sense.

I agree that the main issue of bare feet on an airplane is the gross-out factor. Most people (foot fetishes excepted - not that there's anything wrong with that!), don't find the feet the most attractive part of the human anatomy. I certainly don't want someone's bare feet (even a supermodel's) propped up on a bulkead three feet in front of me at eye/nose level. It just grosses me out...and is usually resolved with a polite request to the offender. I am glad to discover from this thread that there are terms in the CoC to back me up on this.