So, I've said in other places that I have no idea bout collection joints or build ups, so I asked my husband (he just got home last night from finishing up the season-good timing for this thread, lol).
He said that the joint looks slow as all get out. I don't know what type of clerks/agents you have, but I can see this happening-3 for $5 wins slum. Another $5 gets them more slum. At this point, either the kid really likes the "toys" they've won, and he's done... or the parents are frustrated because they're going to end up paying $20 for the smallest "prize".
If you can keep the game moving quickly enough, they may not notice. But those slingshot things with kids playing? Not very fast, haha. And it looks like it may be hard to get an adult to play.
Mike says that if you switch it to a tire, or doniker seat, or life saver that they can throw the birds through, it moves much faster, and you're more likely to get the adults engaged at some point.
Again, I am NOT an expert on build up joints. But I think he may be right. The mini ball next to me for the last few spots this season had slum as it's first win, and I saw VERY little stock walk out of the joint. She got a ton of $5 play, and some $10. But it was hard to get them past it. I don't know. Just my opinions here, since you asked. Ignoring them won't hurt my feelings...