We put a lot into figuring out how to improve things for guests. We spend an enormous amount of time on comfort, the meal, the meeting experience and the sales transaction. Not at all a bad thing. But, it turns out that what happens upon arrival and departure is often more important than what happens in between. Essentially, you get one chance to say hello and good bye. Fail in either of these and it's probably a lasting and underwhleming impression.
Treat someone like you genuinely care about them when they show up and when they leave and you'll be doing something different than your competition and vastly improve your chances to make a friend. So, find your best hosts, greeters and personalities and have them train everyone else in the organization. Those that don't make the cut...well, they don't make the cut. You need to draw line somewhere.