Excellent point and a common error. It is easy to throw a spark at 1 atm. You can see sparks jump many feet in a vacuum chamber. I have tested automotive systems and they can throw a spark 1" in the air. At max cylinder pressure (~150 psig), which occurs at low rpm and WOT (and when cranking), the spark plug gap might be too large to allow a spark. I had that issue with my 1996 2.4L, when accelerating on a highway on-ramp. It would start mis-firing. I lowered the gap from factory ~0.060" to 0.050" and no more problems. That was a Chrysler TSB for the turbo versions (turbo gives even higher cylinder pressure).
