press the yellow fuel key

well I stopped in at a mobil gas station today. I admit i ususally fill up at the discount stations but i figured, it's nearly christmas, i'll give the car a treat with some name brand commodity.

so i swiped my credit card in the self serve pump, i selected "credit" (see post below), i removed the nozzle, i selected the fuel octane/grade by pushing the big yellow box with the number "87" in it-- and no gas came out. I pulled the lever in the handle, no go. the pump kept beeping. I looked at the little screen (which is pretty much invisible if you are wearing sunglasses). it said "press the yellow fuel key." so i pressed the yellow box that said "87" again . . . and again . . . and again. still no go, still beeping. finally i happened to look at the key pad, and next to the various buttons, well i'll be darned, there was yet another yellow button that said "fuel key." so i pressed it. out came the gas.

i am confused. no other pump at other stations asks for this. But even more, why is the "fuel key" the same color as the "fuel grade" keys?? i try to be kind in these posts, but this was just an idiotic bit of design.