Good question. Consult with Philosiraptor for further info.
People can drive to bar to drink, so they do not have to arrive on foot. But they cannot legally leave. So, parking lot is for coming to the bar in an easy way, but not for leaving in an equally easy way.
Completely agree. In the cities however, bars are usually in a block with other commercial businesses, churches, schools, check cashing places and such. In that case there are parking meters in front, but not necessarily for the people who go to the bars. A good excuse to have people park theirs cars in front of your bar, if you owned one.
The city I live in has a lot of that. There is an area called "The Bible Belt" which was named like that due to the fact that, it is the place in the whole city that has the most churches. Incidentally for every church there is, there is also a bar on the opposite corner. How ironic.
There is this strange creature known as 'the designated driver'. This person doesn't drink. Additionally, there is a certain point at which the amount of alcohol you have in your system impairs your ability to drive (normally 0.05% blood volume). If you are below this point you are still legally allowed to drive.