Many moons ago, it was habitual at the gliding club where I flew to slot in trial flights (air-ex, whichever) as soon as was humanly possible. Club members were inconvenienced a little, but most recognised the logic and as WKW has said, could be usefully deployed as well. Results: money for club, good
PR and new members, obviously at a conversion rate concomitant with many such experiences.
It wasn't a really a walk-in sort of place, being, like many gliding sites, far from the beaten track, but booked flights would arrive with family or friends and it was these that often led to the increased membership.
The important thing, whoever walked through the door, was a warm welcome and at least being shown the gliders if the day was poor. We didn't have many members like our Polish chap who was driving along the main road, saw a glider in the air and followed his nose to find the field.