My take: Companies can try to ban the use of cameras and video cameras on their property, but they should provide some direction or training about how to enforce the rules.
I've seem many examples of employees getting aggressive and unpleasant when someone innocently (or otherwise) pulls out a camera to take a picture of something or somone. It takes a lot of tact to enforce this kind of rule without offending the public or your customers. And when you've invited the public to an event like a fashion show or a product demonstration, you should relax the rules.
The other option is to encourage customers and others to document your organization's activities, and maybe provide free publicity. But as Wagner notes, that approach could be risky if your employees and your workplaces aren't up to the task of being documented.
See the group photo pool in Flickr, You Can't Take Pictures Here!