They can nail you with the intention of driving just by having your keys in your pocket or in reach, and especially if you have the keys in the ignition. There was this guy who was asleep passed out in his truck in the retail 20 minute parking once. The cops arrested him after someone complained their back bumper had been scraped and you could see the paint on his bumper. They told me even though the car was off it was a dui cause he had his keys in his pocket.
I dunno how it works truthfully I just never drink if I plan to drive