the reason not to top off fuel in all US cars is the charcoal canister breather gets submerged in liquid fuel and gets destroyed, It will cause blockage while filling up (you will have to fill fuel 1 glass worth at a time - you will have a 2 day beard once done) - it will create stupid vacuum leaks in the intake manifold of the engine (engine vacuum is applied to the tank to prevent evaporation). The leak will be due to the activated carbon particles getting sucked into the vacuum lines and blocking. It will also set Evap system error codes.
Hence all cars in the US have the warning of "do not top off"
Most cases of evap failure in the USA arrive to repair shop after they claim to have poured a litre or so of "fuel additive" - if they used an extended funnel that actually goes through the evap flap, this would not happen. They simply put it on the edge of the tank filler and tipped the bottle.