You know? I have thought about that while trying to use weatherstripping and whatnot to try and lightproof your standard bedroom closet. Brand new completely light-proof tent, but you have to have air intake... and light can get in.
IMHO there are 27 other more important things to worry about other than "light leaks".
For your consideration: People grow weed outside - fact. Headlights from passing cars, full moons (actually, all but a few days a month without some moonlight), and they get fine buds.
I am of the opinion that all those "light leak" hermies are just a strain trait. I have grown a couple of strains that never had an environmental change - OR LIGHT LEAK - that started showing nanners late in flower. I would lean towards other stresses being the cause, or it just being a random act of nature.
Do your due diligence with any grow-space, and get inside and look for light leaks. (if you can fit
) Fix any major issues, electrical tape over any "power on" indicators, etc - then forget about it unless you change something.