I'm only a noob with 1 grow so far but I personally think that light leaks are a bit over hyped.
Logic dictates that outdoors, plants are exposed to moonlight; so light no stronger than that would obviously not have a negative impact.
That argument has been put forth any number of times over the years but unfortunately logic does not control plant reactions to environmental conditions.
Something else to factor in is most people grow crosses rather than pure strains and many strains are not as stable as they are claimed or believed to be and instability in a strain can cause different reactions to differing conditions. While pure strains are not 100% resistant to such things they are far more stable due to thousands of years of nothing but the same genetics being bred back to itself.
Even though I did not know squat when I first began to grow back in 1972 I never had a single hermi until after the so-called wunder-strain crosses were created years later. I am not saying it is impossible to have a hermi in a pure strain, but having one in a pure strain due strictly to conditions are less likely than in many crosses, especially in crosses made by basement pollen chuckers who think they know what they are doing and also from some professional breeders who do not deserve the title of professional breeder.