I camped overnight on a marijuana farm this weekend, where I do some part time organic farming. I was instructed not to drive through the property after sundown because my headlights would screw up the mandatory night cycle the plants needed to flower the bud. I was also told not to walk with a white light lantern or a flash light for the same reason. Instead the land owner lent me her green flashlight that shined a dim green light to go from the main cabin to my trailer I was staying in. I thought she was being a bit paranoid but maybe she's right. I can imagine that the high beams of security lights can alter and mess up the plant's grow cycle. But car headlamps and flashlights?