The staff are very knowledgeable about gluten issues. As soon as you begin your order, mention that you are ordering with an allergen issue and they will make a note of it in the ticket (along with calling it out down the prep line).
The only thing you need to be aware of is if you are splitting a fry order with someone who is not order a gluten free option, you need to make it very clear you want the fries in a separate bag. We've had a few occasions where they oops and put the fries in with the regular burger. They immediately correct the issue by supplying a second, fresh batch of fries at no additional charge. Awesome service, great food!