The clearest large-scale demonstration of how seriously Egyptian religion took the ren comes from what later regimes did to erase it. Following the reign of the female pharaoh Hatshepsut, her images and cartouches were systematically chiselled from monuments and replaced or removed at the order of her successor, a campaign extensive enough that it took modern Egyptology considerable work to reconstruct her reign at all from what survived. A comparable, better known and more thoroughly documented campaign followed the reign of Akhenaten, whose promotion of the god Aten above Egypt's traditional pantheon was reversed after his death together with a deliberate erasure of his name and memory from public monuments.
If a name were merely a label, this effort would be difficult to explain as anything but excessive political spite. Within the logic the ren itself describes, however, the campaigns make direct sense: erasing the name was understood as an attempt to genuinely undo the person's continued existence, denying them the sustenance that speaking or reading their name provided and, in principle, threatening their standing in the afterlife along with their standing in historical memory. The two goals, political and religious, were not separate motivations for the Egyptians who carried these campaigns out; they were the same act described twice.
That the technique did not fully succeed in either case, both Hatshepsut's and Akhenaten's reigns are today extensively reconstructed and taught, is itself informative about the limits of the ren as protection: a name inscribed widely enough, or preserved in enough scattered, overlooked or later-recovered locations, could survive attempted erasure, a possibility the erasure campaigns could not fully prevent.