You need to consider how the air flows in your shop, stagnant air keeps the virus in place, trapped in the air, airflow means the virus travels from one place to another on the air currents. Remember you can NOT see or feel the virus particles. So a barrier stops the virus from free floating through the air. Depending on where your air flows you could be creating more problems without thinking about it. There was one case where the left side of a restaurant had 10 cases come from 1 person, 4 at his table, 4 “downwind” from his table (behind him) at 2 other tables, and 2 upwind from him. But the other side of the place had zero people infected because they were out of his air stream. Hope that makes sense.