My dad was born in 1933.
His father died when he was seven, but when I was learning all about Hindenberg, and Hitler's rise to power, at school, he said his father had told him that he reckoned the first World war (which he'd fought in) was going to be repeated and that Hitler was someone to be frightened of, not mocked.
He remembered him seeing a group of Dad's little friends doing the salute and laughing, and telling Dad that it was wrong, because people weren't taking him (Hitler) seriously...but then he was probably a bit more intelligent than some of the Royal family