I think vapor lock is very unlikely. In tank fuel pump are quite strong.

I had an k-car come into the shop one time that the vent on the gas cap failed closed. The pump pulled fuel out of the tank until it collapsed the metal fuel tank like a beer can.

The car quit running when the tank sucked in on its self far enough to snap the fuel pump off in side the tank.

 

Anyway the link the OP provided says absolutely nothing about vapor lock. Some yahoo was convinced that filling the tank all the way to the top had something to do with the fuel pressure. I think they were getting the EVAP components mixed up.