That, my friend, is exactly why they set legal limits. I've heard of people being stopped at a .20 and barely failing field sobriety tests, because they are drunk all the time. I also know someone that was told that because of their size and body fat % that they would be at a 0.08% BAC after just two beers on an empty stomach. What it boils down to, is that you shouldn't drive after you consume any alcohol.......the life that you ruin could be someone else's.
The thing is that the more that you drink, the more comfortable you will feel about driving.
*gets off soapbox*
That being said, I have a great friend that makes me stay at her house when we get looped......the guest room is labeled 'HockeyMom's Room'.