I remember watching a police RBT show on TV where a guy had stuck to the guidelines of 2 drinks in the first hour and 1 each hour after (that seems like a ridiculous amount of alcohol to be driving with in your system to me) and was over the limit. He was baffled by this, which made me realize that not everyone hears the small print, that this is a guideline only and everyone is different.
I don't drink anymore, I think I've drank twice since I fell pregnant over 3 years ago but when I used to drink, I'd have one drink with dinner then drive home a few hours later. I felt fine doing this but interesting points are raised in this thread where drink driving is not ok, but a little bit is.
I've never really thought about this so it's an interesting topic for me!