A lot of people don't know why Mister Rogers always wore cardigan sweaters. His mother made some of the first ones for him that he wore on TV. The reason that he wore long sleeves and sweaters all the time was to cover up his Marine Corps tattoos. He was a Marine sniper par excellence during the Korean War, and racked up many decorations for his outstanding valor. This is all true, it's public record, so if you don't believe me, look it up.
It's a good thing Mister Rogers is so nice - otherwise, he'd pick your sorry ass off at over 1000 meters...By the way, Bob Keeshan (Captain Kangaroo) was also a Marine hero, in WWII on Guadacanal.