The problem with most trade show qualifying questions is that they’re black and white, and they’re far too focused on identifying pipeline stage and purchase readiness.
That’s not a bad thing to ascertain in general, but at a trade show your prospects are overwhelmed already and not in a buying/evaluation mindset. Asking questions about their qualification and readiness to purchase can come across as too much, too fast.
Instead, ask questions that are both conversational and situational. Listen for any of a series of buying signals (based on needs, pain, symptoms) that determine whether the prospect has a situation or problem you might be able to solve.
Questions like this could include:
Why are you here?
What are you looking for?
What do you need to bring back to justify this trip?
If you get positive answers to these questions (based on your buying signals), it’s appropriate to ask about timeline to solve said problem. That gives you, effectively, a two-stage qualification process at your next trade show or event.