EDIT: So this my hypothesis of what happened. I used the invite and that seems to have whitelisted the IP of my school. Therefore now the kids in my school can download and brrowse the safenetwork without signing up.
Just wanted to point out that even if you aren't trust level 2 and don't have an invite, you can still browse SAFE sites without creating an account.
So even though you won't be able to test out the demo apps such as hosting, mailing and generating a public ID, you can still browse sites without signing up.
So, if you want to try it out, go ahead, download the SafeBrowser and visit the sites around!
1) Downlaod the latest version of SafeBrowser: https://github.com/maidsafe/safe_browser/releases/tag/0.3.0
2) Browse around a few of the SAFE Sites: