Well, there is a way around this. You will need two things (besides your camera) – a steady tripod and Adobe Photoshop CS3 Extended.
Set up your tripod in a place where it won’t be bumped by anybody, compose your shot, and start taking pictures (preferably using a cable release). Make sure to set your focus manually and turn the autofocus off. Since the camera is mounted on a tripod, you also should turn off the image stabilization on your lens (if you have this feature). The idea is to expose all the stationary elements of the scene in a series of shots. The number of shots and time between them will depend on how crowded the scene is and how quickly people move about. Take note of people sitting on benches or standing in the same spot without moving. It is best to set your camera on manual exposure – hopefully the light won’t change too much during the shoot. Aperture priority mode will also work.
When you return home, open all the images from the series in Photoshop CS3 Extended. From the top menu, select File >Scripts > Statistics. In "Choose Stacks Mode" dialogue, select "Median."
That’s all there is to it! After crunching some data, Photoshop will spit out a new image without anybody in it. You may need to use some of your individual files to clean up a few artifacts generated by the process. In this example, I took 25 exposures during approximately 15 minutes (the place was incredibly busy as you can tell from the first picture). The clouds had shifted, so I "borrowed" the sky from one of the shots.
Now how about taking a photograph of a highway interchange in downtown with no traffic?
You can view Alexey’s Shutterstock gallery here.