I would agree that carrying gasoline inside a vehicle should be avoided so far as possible.
If in doubt about the accuracy of the fuel gage, then top off every xx miles so as to ensure that the tank is allways at least 75% full.

In an emergency, you may need to carry spare fuel inside the vehicle, the benifits arguably outweighing the risks in such cases as fleeing an emergency with little chance of re-supply en route.

I would not carry spare gasoline routinely.
If you need to take gasoline home for a generator, lawnmower, boat engine etc, I would take the shortest sensible route, in daylight, in fine weather and drive with extra caution.

If considering a new vehicle, there is much to be said for a diesel one, not only is the fuel mileage better, but diesel fuel is much safer to store, and if needs must even to keep in a vehicle.