Hi, Just checked on my 2011 Jazz, as I had assumed also that the petrol filler flap was held shut with a catch
but it is not. It is possible to get your finger nail or similar devise and open the flap. Once the car is locked this is no longer the case.
There is no rubbing of the body work on the hinge side, the flap moves well away from the panel on opening.
Hope this is usefull!