Getting home after the Kentucky Derby is hard. Even if you've managed to keep track of the people you started the day with (a task more difficult than actually making money at Churchill on Derby Day), and even if you have a suitable vehicle within walking distance, there's a good chance that none of you are sober enough to get behind the wheel. Toss in the fact that cabs are few and far between, and that the Tarc will take you to Churchill Downs but it won't take you home, and suddenly you have yourself a massive issue.
The result of all this is that year after year hoards of drunk people are left scrambling to find a way to either get home or get somewhere else to keep their evenings going.