Stressed ladies don't grow well. Changing their light spectrums and light rhythms is stressful.
For some strains, (especially if already stressed) one "oops" wipes away ten "atta-boys". During flowering, one trip to the smoke shop after work, or stopping by the grocery store for munchies...can and will have very negative results.

Best to do what you can to eliminate causes of stress before it becomes a problem. You'll already be tied to the plants till harvest, might as well make 'em shine. :thumbsup: