Quite obviously they are not teachers. It is stated that they are working for a large company. They have security guards, accounts and a post boy. The "art project" was a design project and they've been doing "team building" all the trappings of a faceless company.
phew I thought I was starting to go mad for a minute..I knew they was not teachers, maybe they are an advertising firm, that seems to be the most logical answer to me.