In the scene where Lucy (Shelley Long) is at Phineus Deveroux's 4th of July party, you'll see the tuna cooking on the huge barbeque thingy. The tuna looks like its actually cooking. But look at the coals. When coals are hot enough to cook, they're white, not jet black and looking brand new. Also, notice when she spills the lighter fluid on the fire. The fire is in front of the coals, not directly in it.