Getting a driving licence and being suspected of drunk driving and causing a crash are two different things. Where I'm from your blood would be drawn after you were arrested for a suspected criminal offence, not just because you had a license.
It is a condition of getting your license that you will consent in that event, at least in the US. [1] It would be interesting if someone who was driving illegally without a license could get away with not consenting to a breathalyzer.
