The use of the term art medium is, to say the least, misleading, for it is the artist that creates a work of art not the medium. It is the artist in photography that gives form to content by a distillation of ideas, thought, experience, insight and understanding.
When I first became interested in photography, I thought it was the whole cheese. My idea was to have it recognized as one of the fine arts. Today I don't give a hoot in hell about that. The mission of photography is to explain man to man and each man to himself.
The most successful Subway customers, of course, are the ones who can't keep their hands off their sandwich. Join your artist in the sandwich assembling process. That sneeze guard is a suggestion. That sneeze guard is trying to intimidate you into staying on the customer's side of the partition.