New water heater installed. Door vents need to be opened?

New water heater was installed today. After installation was completed I was asked why the vents on the door had been covered. I told him the gas company had covered them up about two years ago.

He said he wasn’t sure why they’d do that because the water heater needs those vents.

Before I pop those vents open (they are covered on the front side of the door) is there any reason why the gas company would be at odds with the plumber? Why would they cover them up?