I do not believe a person can lie their way out of a DUI hence the water example, where it can be answered truthfully.
The point I was making, the question (how much have you had to drink) entraps anyone answering it who has anyone even one glass of wine with diner and nothing else. Technically one can be considered impaired even if they blow less than .08 no matter how slight. So by answering the question truthfully, one has admitted guilt. Also the police can lie to you but you can't lie to the police so it's a catch 22.
I do not drink and drive but I do not like to give up my individual rights by answering a question designed to take those rights away. I'm guessing police have other questions designed like this for other issues as well, e.g., how fast you were speeding, etc.