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. 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.