Well yeah, it's at the officer's discretion to determine if you're impaired based upon evidence to go along with the breathalyzer. So yes, you can be given a DUI even if you blow under the legal limit, technically. The point remains, that as long as you're not showing obvious signs of being impaired, and you were to blow under .08, I would say the vast majority of cops aren't going to tag you for DUI.
And makes sense for you, since you live in NYC(pretty sure you're in the city, itself?), where public transportation is easier than if you lived out in the suburbs and wanted to hit a bar, or have a drink with dinner or lunch.
Never said it's important. Just asked you a question.
I'm not saying people should drink and drive. I'm just pointing out that I don't think there's anything wrong with someone having a drink, or glass of wine, or a beer with their lunch or dinner, and then driving. Most of those people would likely blow 0.0, and I'd argue the vast majority wouldn't be visibly impaired in any way, either.