I have the wet red type of blood, if that helps.

Seriously though, I have been injured badly enough at least twice that they had to give me blood.

I do not remember any emergency personel ever asking me what my blood type was. Not at the scene, not in the ambulance, and not at the hospital.

(One of the times they did repeatedly ask me my name, who the Prime Minister was and what year it was. It was very annoying.
How can you trust doctors who don't know simple stuff like that?)

I am not a medic, nor was I ever military, so I might have some of this wrong, but I do remember they used plasma one time.
I think it was because with plasma they don't need to worry about blood type.

Edit:
Repeating disclaimer; I am not a medic, nor was I ever military, so I might have some of this wrong

I wonder if they put the blood type on the tags in case they need donors in an emergency. I seem to remember hearing about field transfusion kits being supplied with no blood bags to medical corps years ago.
They could not carry blood, it would rot, so they were expecting to use the two legged blood bags they had wandering around.