Sorry for the late reply. Since the ID is not a # variable in the URLs, it is passed to the web server hosting the content, meaning even if the data/metadata is not stored on any server you own (it doesn't appear to be), you could still be expected to block URLs which someone wants to ban.

# variables are not part of server queries, so they are better for user privacy as well (not stored in server logs). I'm not saying you won't ever get takedown requests with #, but it is easier to argue to authorities that Peerdium is merely a user-ran software you are not in control of when using #.