Any good time-suck-blocking extensions that are password controlled?

In My Humble Opinion (IMHO)
#1

My son is participating in a pilot program at his middle school where Science is an on-line class. One day a week in the classroom for labs, everything else -homework, tests, discussion - is on-line and at your own pace. This past weekend while doing classwork he got sucked down the YouTube/DeviantArt/Wikipedia/TvTropes hole and spent 6 hours doing something that should have taken about 2. I can sympathize, I’m on the Dope at work right now.

I was think of helping him out by installing a time-suck blocker such as Leechblock (Firefox) or StayFocusd (Chrome), so he can access the class website but not much else during his class time. However, all of the ones I’ve seen are timer-based and are designed to not be easily circumvented in any case. After all, the entire point of these extensions is that your willpower is weak so they should be difficult enough to turn off that you remember to get back to work.

What I’m looking for would be something that can block the time-sucks, but I can turn off with a password so when he’s finished with homework, I can simply turn off the block. Does anything like this exist?

#2

You can do that in Leechblock, just specify the lockdown for a long time, and then use the password to end it when you are ready.

Unfortunately, leechblock has a MAJOR weakness which a smart teen would be able to figure out quite easily. Spoilered as if you know it, leechblock becomes useless.

If you shift-click firefox, you can open safemode and leechblock is disabled, if anyone knows of anyway to disable safemode, please tell me

#3

It’s doable, but it involves a sort of “hacking” of browser.jar file. Even then it’s not super hard, but the main problem is that it is quite tedious and said file may get replaced with any automatic update, so you’ll have to check and see if you’ll need to do it all over again every six weeks or so.

It’s a lot easier to just embed the addon in question into Firefox itself, so it can’t be disabled, even in safe-mode. Just download the extension as a separate file (right-click > save as), then rename it from .xpi to .zip, then double click it to open it. Open a new windows and go to the Firefox main folder and create a folder called “distribution.” Open that folder, and create a folder called “bundles.” Open that folder and create a folder that has the same name as your extension file. Then copy the files from the ZIP file to the folder.

Make sure Firefox is completely shut down when you do this. Only start Firefox after you are finished. This doesn’t work with every single addon, though, and I haven’t tested it with the addon in question. I suggest making a backup copy of your Firefox folder before doing this. (Just copy all the contents to a folder on your desktop or something.)