Those are just Sodexo (on campus catering company) employees wearing their work uniforms in the group. There are chefs, janitors and servers in the group. As a BYU alum and Zags fan it caused me to do a double take and I was glad to see it wasn’t what I thought it was.
Gonzaga has been very proactive about the students respecting BYU and would hate to have a misunderstanding cause hard feelings.