How do you test a photo menu with real guests?

Two tables are watched looking for a dish in the photos and finding the price, without help. It is not tested with the team, who already recognise every image. Watch a quiet service until they order or enlarge the wrong photo. In the sierra the owner scrolls the gallery on their phone and assumes the table also reaches the wine. Which photo confuses them is noted, and that card is fixed before the rest is touched.