I know from experience and some introductory study of the laws of Niddah that rabbis typically try to find leniencies wherever possible in issues of family purity. In many instances, a Posek will rely on a technicality to permit a husband and wife to be together even though common sense might dictate that the likelihood is extremely low that a particular stain, or even series of stains, came from any source other than uteran blood.
I appreciate the delicate nature of these questions, as well as the importance of finding ways to be lenient in these matters. I also understand that in many communities, women must trek far distances, even today, to get to a Mikvah, and that even when a Mikvah is easily accessible and clean some women find it difficult to go.
But in instances when the rabbi knows that a woman can easily access a clean, warm, Mikvah with friendly attendants, and the particular woman asking the question enjoys the experience and has no emotional or personal difficulty getting ready or accessing the Mikvah, why isn't she encouraged to be stringent and go "just in case", when the leniency being applied is based on a technicality and the woman wouldn't need to separate from her husband for any extra time (she could go that night)?
I understand that we don't. But why not?