A single beer could put someone over .02
I realize that my own physical alcohol tolerance is quite low, and that one person does not constitute evidence, but that said:
If I consume any normal serving of alcohol, a pint of beer, a glass of wine, a shot of something stronger, I am probably not fit to drive immediately. I must consume food and plan any driving carefully. Can I have a beer at lunch with the guys? Yes, ONE... if it's more than one drink it's going to be a long "lunch".
Everyone is different, however the standard being bandied about is four drinks in an hour, even with food that leaves me incapable of driving safely. I have observed myself and others in these scenarios and as a result I do not believe (and again this is about belief and personal experience) that driving with 0.08 levels is safe, consequently I would be strongly in favor of reducing the legal limits.
For me the calculus is very simple, either restrict consumption to a bare minimum or just don't drive.
(Now this may make me sound boring, but when I don't have to go anywhere, say a nice cottage party where the stagger home is 200 feet, I do drink enough to make the most alcohol resistant at least tipsy... )
The upside of low alcohol tolerance? Drinking all evening is very cheap if you're only downing a drink or two per hour.