I suspect that there may be a duty of care issue here.
I never passed "Tenderfoot" in Cub Scouts and my feet will automatically find anything sharp or dangerous however well hidden.
You can bet that the "shoeless" will also be the first to yell for the courts if they stub their toe on something in the aircraft and that is apart from the attendant blood and other unsanitary matter that someone is going to have to clean up.
The profile of a "shoeless" is not one that would encourage me to allow them on board without demur.