Do you find that you're actually being prevented to talking to a real sales person or engineer at shows? Usually the models are there to keep the queue, since it's rather cheap to hire attractive and outgoing people to do just that. It's probably just a reflection that sending FTEs to shows is expensive, so there might only be a few of actual employees there. But the models should be helping you get to one of the FTEs as soon as possible - that's pretty much why they're hired.