It's possible in an upright engine but you'd really have to be trying
Say you'd filled your tank then went off talking for 30 minutes and all the while the tank was syphoning into the carb. If the crank port was open then it'd run into the crankcase. Hit it with the starter and enough fuel might get thrown through the transfer port to fill the combustion chamber. All it takes is about 1cc of fuel for a .60 size engine. But that's one of the advantages of an inverted engine...any fuel that syphons through just dribbles straight out of the carb onto the ground (so long as the barrel is cracked open slightly).