My take on this is....I think nurses generally don't like for a person to think for themselves, if you have a 'condition' and are told to take meds for it by a doctor (read God) then you should never ever alter that med by yourself because 'what do you know', you're 'just a patient'. However the doctors and nurses aren't with us during the night when we wake up hypo or whenever else, it isn't their life on the line, it's ours, so it's OUR diabetes and up to us to care for it as best we can with the medical profession as our guidance and helpers (and prescription writers, thank you very much). However, when sitting in a car you're in charge of a lethal weapon, I don't see the problem with testing your bg to see if you're at a comfortable level before starting out, that's basic self care (and care towards every other motorist on the road also) and it's not like it's difficult to do or anything so why wouldn't you?
Also if I were in a hypothetical accident (which hopefully none of us will be) how awful it would be to be held responsible for that if there was no evidence as to the level of blood glucose in the blood. And that's not even going as far as considering the possibility of being hypo and actually being responsible for it. It's a legal argument, take your blood sugar reading, it ensures you know you're good, it means that if in (worse case scenario) there's an awful accident you have evidence that it wasn't down to being diabetic and being hypo, that you took due care of yourself, your passengers and anyone else on the road around you.
I know the feeling when the medical profession goes into a tizz about a possible hypo (that hasn't happened for years and isn't even likely to happen in the near future) but also you do need to cover your own self too in all senses. Seems like a no-brainer to me.