It shouldn't vapor lock if you plug it. The vented gas cap lets air in but pressure will build up if it is plugged. It may cause a leak.

If emissions isn't a problem then I say remove it and vent the tube to the underside of the fender where it won't potentially drip on an exhaust pipe.

Even if removed it shouldn't leak because the back of the car has a vapor separator and the liquid fuel should get put back into the tank but better safe than sorry.