If the concessions are inside then there would be no saluting. Same in the military. If you are outside when the flag is raised/lowered you stop and salute. If you are indoors it's business as usual.
Unless the concessions are outdoors and inside the stadium area I don't know what being at the concessions has to do with anything.
Unless the concessions are outdoors and inside the stadium area I don't know what being at the concessions has to do with anything.