The belief that unfurling a rain shield inside a building brings misfortune is a superstition deeply ingrained in numerous cultures. It represents a perceived violation of the natural order, where such protection is intended for outdoor use against inclement weather. The act itself, deploying a device designed to ward off rain within a dry, enclosed space, is viewed as an invitation for negative occurrences.
This superstition likely originates from a combination of practical safety concerns and historical context. Early umbrellas were unwieldy and potentially dangerous to open indoors, posing a risk of damaging objects or injuring individuals. Furthermore, in past eras, weather patterns and their impact on daily life held a greater significance. Invoking the need for protection from the elements within a shelter could be seen as tempting fate and inviting hardship. Its persistence is strengthened by its historical context.