[PeteH]

I have had fuel drip from the tank vent hose when full or nearly full on two different cars, especially if the temperatures have warmed up. It's a real pain when it happens on a lift and drips on the car below! I have been known to connect a hose on the tank vent tube, and stick the end in a clean cat food can to catch the few drips that may come out.
I was spooked last month when the garage smelled strongly of fuel, it was from the tank vent tube on the under construction FF 289 FIA, it only has about 3-4 gallons in it, but still must have vaporized and condensed when the outside temps warmed up. Ethanol content may contribute to the problem.