Well, even if they don't do that, then it doesn't mean any other user couldn't do it. It could be some kind of unofficial demo site. If someone is interested in doing so, the important things to take into account would be:
1. Cleaning the site frequently and automatically (once a day/every X hours/etc)
2. Having the site updated and mentioning which commit it is using
3. Allow admin access
4. Not having any non-core plugin (I guess the ones delivered with the core should be included and enabled so that they can be tested)