Apparently, this rule has always been in place. Event staff just never spent a lot of time and attention enforcing it. A prime example of this would be last year’s flesh-fest over at the RYL booth:
If you have a keen eye, you will notice that the girls have an extra piece of black fabric surrounding their posterior in the second picture. Why is this you ask? Were they getting cold in the exhibition hall? No, they weren’t. The picture on the right is taken on the second day of the show, after the models were warned that they were being too provocative. As a male, I didn’t know that was possible..
You can read more about the boothbabes at The Tech Zone.