If someone would be nipping a bit of bud just to have something to smoke I would agree with taking a bud or part of a bud from a lower portion of the plant. If someone was nipping a bit of bud to test to see if it was time to harvest then I would not suggest taking bud from a lower portion of the plant. It will not be as advanced, as mature/ripe/ready and not be representative of what is above it and not really tell you if the time is right or not.