I used to own a motorcycle (BMW R1100RT), whose filler neck was designed to preserve a small bubble of air at the top of the tank; it was in this bubble of air space where the hose from the evap cannister came in. Some other owners chose to modify their tanks by drilling a small vent hole at the top of the filler neck, allowing them to put an extra few ounces of fuel into that air space. Many of them reported problems later: liquid fuel was getting all the way to the evap cannister and washing granules of charcoal down the hose to the left throttle body, manifesting as black crud showing up in the intake port,
The other problem this caused was when owners refueled their modified bikes and then rode a short distance home and parked. The fuel would expand, and with no air bubble at the top, the liquid would go to the canister…and then out the vent line to the floor of their garage.
In severe cases the vent hose could be blocked by these charcoal granules, resulting in an inability of the tank to relieve pressure or vacuum.
Note that these were problems that arose specifically because of aftermarket modifications; the bike was originally designed to protect itself against overfilling, and I would expect a car to likewise be designed to avoid those same kinds of problems.
FWIW, I just checked the owner’s manual of my cars for the refueling procedure. One says this:
Stop filling the tank after the fuel nozzle automatically clicks off. Do not try to ‘‘top off’’ the tank. This
leaves some room in the fuel tank for the fuel to expand with temperature changes.
The other says this:
Do not attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically. Continued refueling may cause fuel overflow, resulting in fuel spray and possibly a fire.
I checked online for owner manuals of several other cars. They all instruct against overfilling, and some warn of overflow/spillage/fire as potential consequences. None warn of potential damage to the evaporative emissions recovery system.
As @LSLGuy observes, a couple of extra pints isn’t much; on a 15-gallon tank, that’s an extra three percent. Bigger gains can be had by changing one’s driving habits.