Ick, I wouldn't wanna lug those plants in every night, that means you have to be HOME every night...lol...But no, I know outdoor plants don't have as strict a need for complete darkness during the flowering cycle, and I bet that during flower, one way or another, that street light doesn't come on, or it's so old and dilatidated that it gives off barely more light than a full moon. Shit, I'd just tape a can of spray paint to a 8 ft. pole, and tape the nozzle down so I could spray from a distance and black it out.