I’m sorry if this is the wrong place for this kinds of suggestions. I’m still a relative newbie.
The trend (at least in Finland) seems to be that fuel stations no longer service cars. There are unmanned fuel pumps that accept bank notes (bills) or cards as payment, and there are combined convenience stores and food outlets that happen to sell fuel as well.
I’m proposing that the POIs for fuel stations should be tagged amenity=fuel,shop=convenience when appropriate. This would allow a translation into the Garmin symbol 0x2e06, which is displayed as a fuel pump symbol on the map and shows up in two menus: fuel stations and convenience stores.
Currently, JOSM displays such a hybrid as a shopping cart symbol. I didn’t check Osmarender or Mapnik, and I haven’t uploaded any points tagged amenity=fuel,shop=convenience.
I posted a separate topic for the Garmin related aspects of this.