HN user
I could be wrong, but I would guess that they're not mounted overhead for that reason. At least not directly overhead. Since the court is a known, fixed size, I think you'd be able to project the players' location from a normal camera view onto an overhead representation like they show in the article's videos.
Amazon has also had them in the UK, since at least September 2011 (http://www.pocket-lint.com/news/41989/amazon-locker-invades-...) which is almost a year now.
I moved to the UK from the US last December and thought it was a cool idea when I first saw one. Definitely makes sense in a city - more so than suburbs.
This is an interesting use and I like the idea, but I don't think it makes him wrong. You don't actually need an ORM to do this. The same logic could be applied to data sets retrieved through regular queries. Or you could create views/stored procedures with the same logic.