Phillip, I think the problem lies in recommending people do it that way. You don't know their water quality. My water smells like a pool. A fish would die in it without condtioner/dechlorinator. So, taking your advice would end in death in my house. But honestly we take that chance anytime we advise something to someone without knowing everything.
THAT'S why I rely on test kits, the health of my fish, and common sense to tell me what's going on. All the staring in the world won't tell me when my tap water has had a large ph shift and when I should be careful because of it.