This is an absolute that just plain isn't true. For instance, out-of-state PD calling my sister-in-law from an unrecognized number to inform her that her sibling had died suddenly. There are numerous instances where an unrecognized number may need to contact someone for an emergency. I don't say this to disagree with the general sentiment of your post, but I do disagree with that particular statement.
This is an absolute that just plain isn't true. For instance, out-of-state PD calling my sister-in-law from an unrecognized number to inform her that her sibling had died suddenly. There are numerous instances where an unrecognized number may need to contact someone for an emergency. I don't say this to disagree with the general sentiment of your post, but I do disagree with that particular statement.