My college once held a fundraising dinner, complete with valet parking, coat checking and a full dance orchestra. I ended up becoming the door greeter. Guests had a few questions about where to check their coats and how to find their tables, so I helped them as best I could. I also had to keep an eye out for anyone who was not an invited guest.
I felt pretty good about providing a little bit of security for the guests, too. Everyone else was busy parking cars or checking purses and coats, so I was the only one who couldn't be distracted from my post. I can see where residents of an upscale apartment building would appreciate knowing someone was guarding the door and screening visitors.