Google's "swamp" feature can disable any extension on a school chromebook.

Here's how to get it

Go to Settings>Network>Wi-Fi

From there, click the arrow next to the Wi-Fi name.

Scroll down, and go to Network

Go to Name Servers>Custom Name Servers

Enter in:

129.213.58.41
129.213.58.41
129.213.58.41
0.0.0.0

In the address bar, type in chrome://settings/clearBrowserData

Click "Cached images and files" and hit "Clear data".

In the address bar, type in chrome://restart

After logging back in, go to ssl.google-analytics.com

On the white screen, type "thisisunsafe" on the keyboard.

You will then be given a link, to copy and paste into a new tab.

Scroll down to "Disable Chrome Extensions similarly to LTBEEF"

In a new tab, go to "chrome://extensions"

Click on the extension you want to disable, go to "Details".

Next to the address bar, copy the string of letters next to the "?id=" signature.

Back in swamp launcher, paste the ID in the "Extension ID here" box, and click "Disable this extension"

The extension can be brought back by either clicking "Revive this extension", or going to chrome://restart

Happy New Year 2013!