I knew I should have checked the link before asking! Thank you for indulging my laziness.

I suppose/guess maybe they're afraid that if they made such a path, there could be an accident (people might stumble and step on one, something like that) that would damage the display. Or maybe they're afraid people would try to snatch one. Still, especially if you want to comment on the human collective future--well, I think I would have been tempted to make a different decision, even granting the risks.