Like how so? Some (/me gasps) think perfectly cooked is "well done", yet others its med-rare to medium. (medium here)
From my understanding as a grill cook (ala a decade), air exposure is the big factor in killing the dangerous bacteria. Processed meat, such as ground beef is much riskier to undercook because of all the air/bacteria it is exposed to. Steak and other cuts of beef on the other hand, charring the outside takes care of most of the dangers. I do agree though, i don't want to chew rubber, although I have made quite a few "Pittsburgh Rares". Charred on the outside basically raw in the middle. Apparently it came from the Pittsburgh area as the coal miners would throw their steak on the coal fires and burn the outside very quickly.