At a Trade Shows the objective is often to attract as many delegates as possible to your stand, but that approach often wastes your sales team's time. If 50% of the delegates have no requirement (or purchasing power) for your services, why bother introducing them to your sales team?
In my experience it is all about the quality of those delegates being introduced, and the only way to increase the quality is to qualify them before introducing them to your sales team. This is where my skills as a sales person come to the fore... A couple of well placed questions at the first point of interaction decides whether the delegate sees 20 seconds of magic or is 'warmed up' with a few minutes of magic, before being personally introduced to your sales team.
A positive return on investment (when using my services) is the most important driver here, and that can only come from introducing good quality sales leads, something I have a lot of experience doing.
The typical value add's that come from using my services include - increasing brand awareness, creating an air of expectation on your stand, attracting repeat visitors and giving all of your key prospects a lasting magical memory from visiting your stand.