Seat Pins
I've only ever been strapped into three bang seats, and they were all the same, and the last time was in 1975. That seat needed 80 knots forward speed to work at ground level. Nowadays I can't afford to fly anything with a proper bang seat, although a recent offer relating to a JP5 was very tempting.
No pins to check, but (IIRC) fifteen things to look for before sitting down; 5 reds, 5 blacks and 5 greens.
Then, if all looks good, check, again, the last red, and sit down. Strap in, taxy, and when ready for the off, reach up with right arm and move the red golf ball that is pressing against your neck, to a point over your right shoulder where you can see it.
On landing, make the seat safe by pulling the golfball ball back to where it presses against your neck, reminding you that seat is not going to fire.
Clearly visible by the Caravan controller as well as the Lineys and other members of the formation, everyone knew if your seat was armed.
Why did that never catch on?