Because of this, one of the easiest ways to improve your odds of success, when you own a restaurant, is to lease LESS space than you need. Basically there's a lot of good reasons to make your customers wait in line:
1) You're not paying to rent the sidewalk in front of your restaurant
2) Having a few customers waiting out front is a great advertisement for your place.
Obviously, this isn't great for customers, but if you're a restaurateur it's awesome.
Out in Vegas, restaurants and clubs routinely pay people to wait out front to make their place seem "in-demand."