Have you ever seen or killed the Courier?

LiannaSilverwind: As Courier Survivor Champion I will add...
1) Very often enemy team rushes in order to kill the Courier. If the allies defend, they can easily farm rushing attackers and win the game. Courier will usually survive.
2) Very often enemy team will try to find hiding Courier even losing the battle due to timeout. Courier will survive if he/she uses fast vehicle.
3) Couriers are different people, we had about 50, maybe even more, different people playing Couriers. Some of us were supercampers, some were aggressive attackers, some of us were running all over the battlefield. Some Couriers do use only gold ammo. Some never use it.