Very odd indeed, as I have had no trouble seeing other people's wallpaper selections, and in fact before respoding to Giancarlo's post, I logged into Home to make sure I wasn't imagining things. I saw a few GTPers online, including Sprite. I asked if he wouldn't mind inviting me to his Harbor Studio to see his wallpaper... yeah I know... it sounds bad, so I made sure he knew I hadn't lost my testosterone levels and switched teams.
Any way, not only did I see his wallpaper, but I asked him to change it, and invite me back in after I left. I did, and voila the wallpaper had changed.
If you don't believe me feel free to PM Sprite and ask him.