Any time you stress them or change their schedule, it slightly increases the chances of hermies. Let's just hope the lights weren't off for 3 days, but even if they were you'll probably be alright as hermies are fairly rare. That makes me wonder, does anyone know of any studies or articles about the percent chance of hermies with increasing change of schedule? I tend to think, that if anything happens your plants will decide to go back to veg, then back to bloom with the old light schedule, and this may take a couple weeks out of bud development. If so, I think your plants would just take a couple weeks longer to ripen.