Gas Cap - new cars still have them ?

[JeremyH]

Can't believe you guys with physics degrees are debating this without seeing a schematic of all the vapor recovery piping, pumps and the excess pressurized fuel flow return that people with engineering degrees designed. There's more to analyze than just a fuel pump and fuel cap / door.

I searched for more info on it, but could only find generic pictures of the door and the flap on the outside...which didn't answer my questions.

I have never seen anything like this, so it is a bit difficult for me to visualize...