I was asked.... and he took my word for it.
I didn't get a BT done (tho I did have to POAS again... thought that was a bit rude).
My EDD has always been based on my dates and not by the scan dates (although I haven't had a proper ultrasound yet). I even had my FF chart printed out but I didn't need to produce it.
I have a short scan each time I see my doctor and, so far, he's been happy that the growth of the baby is consistent with my dates.
I guess each doctor/midwife differs?
Considering they're all 'estimates' anyway, I don't see why they can't just take your word for it.