There are numerous was to herm a plant, plants can in fact herm themselves! There was a time in the 70s when most weed that came from Columbia and Mexico was seed ridden. Then the Mexicans figures out how to grow sensimilla, but in super large fields hermies were an ever present thing and so even sensi had the occasional seed or 20 in it, all depended on the wind. Let’s face it indoors the light is 100 percent on and then BAM its dark. Outdoors the light intensity builds as the sun rises, peaks and sets. The moon is a factor, does it cause some plants to herm? Maybe? Is a pinhole gonna hermie your plants? Maybe but I doubt it. Anyway many germs are not covered in male flowers, maybe just a few show up? Just pluck them as they show up.