You should never put food over your infra-red burner if the burner is not lit.

The infra-red burners are designed to incinerate the drippings from your food. If the burner is not turned on this drippings will rest on your burner and clog the burner preventing proper air flow the next time you use your grill preventing the infra-red burner for working properly. In some cases, this will cause the ceramics to crack resulting in the need for a new burner.