Mothers have a monopoly on wisdom because only they know how dangerous the world is and understand one can never be too safe. As kids my mother used to constantly harp on my brother and I about sitting too close to the television. She used to say it would 'ruin your eyes' but then later cited 'exposure to all that radiation' as the negative side effect. Similarly, she made us stand back 10 feet from the microwave and advised us never to look into the microwave when it was on ("or else it will burn your eyes out").
The source of mom knowlege has always been obscure to me but I swear it's universal. We were taking Junior for a walk one time along a stretch of road that had a 6' bike lane but no sidewalk. MIL happened to be along and admonished us inattentive parents for allowing Junior to walk on the grass so near the edge of the bike path. She evidently thought it would be much safer if he walked in the grass at least ten feet from the bike lane.
Any recollections of (what you thought were excessive) maternal safety dictates as a child? Any current mothers care to fess up about how they're being overprotective?