Thanks Mark! I guess they do some kind of minor blocking which is why Google only indexes it if you make it public.
I did actually ask them and they gave a similar robots.txt answer. I’m not really sure how to specifically block http://url.s83596.gridserver.com/ with the robots.txt – as far as I know you can block files and folders, not urls.
But it seems it won’t be a problem since no one else has really complained about this before.