I can understand with electric but gas i dont know - i am using baco foil on mine to keep clean and it has not caused any problems yet - if it does catch alight what damage can it do with a bbq which has a gas burner ( gas supply pipe is only possible problem i suppose ) - my baco foil which lines the sides pushes heat upwards as well but i open and close lid as req'd dependant on temp - everyone to their own but i have had no problems with using my bbq - people cook joints in ovens using bacofoil - so i dont know