I dont think EMS gives it anywhere near me, but maybe like the previous posters have said, its more to get you to think outside the box.
If you ask the pt, then you can tell the triage nurse, and it can be done while the pt waits for the doc. Sometimes triage forgets to ask, so if the medics already know the pts tetanus status, and relay this information its ensures the pt gets the needed vaccine and doesn't have to wait for it later.