It's possible. In the case I quoted the bloke already had 3 points. Add the mandatory 10 for Drunk in Charge and he got a disqualification. I thought OB were being a bit picky in that situation, could have just told him to turn it off and given him a bit of advice; unfortunately sometimes, for...
Quite possibly you are technically but it's unlikely you'd give OB any reason to search you and if you did, they would still have to prove to a court that you were "in charge". It's a bit of a grey area and I've only come across it once in "real life"; a bloke was in the car in a supermarket car...