Met a chap on the OCU at ISK in 93 who wore his great grandad's RFC cap badge on his forage cap
When I mentioned it he said, "Yes, been wearing it for 3 months now, you're the only one that's spotted it"
The only thing that gave it away was it was old brass that looked like 24ct gold, and had been Brasso'ed away to a fine lace - still looked the part though