You do need to watch them to make sure they are changing gloves and avoiding cross contamination. I've had to stop them a couple times because the touched a bun and then touched my food. However they are very apologetic and willing to remake my food. Make sure you tell the cashier you have a gluten allergy so the staff can take the proper precautions.
They have a dedicated fryer, they have separate areas for meat and buns, and they will change gloves. Five guys is considered safe in our area (Utah), so we decided to give this place a chance as we were driving through California. My celiac son just ordered the meat only (they can do it in lettuce, he just doesn’t like it. They do not have gf buns) and fries. He did not get sick
The employee at the registered spoke very knowledgeably about GF celiac safety. She immediately explained their safety practices. They have a dedicated grill for buns and the fryer is only for fresh cut potatoes. They offered a bowl or a lettuce wrap in place of the bun. They cleaned a separate prep space and their hands and changed gloves. The order slip/receipt was marked “ALLERGY”, the meal was bagged separately. They called out “Allergy” multiple times to the staff touching food.