Disables some "Remember Me" checkboxes on Firefox. GreaseMonkey user script.

forget-you.js

// ==UserScript==
// @name           Forget You
// @namespace      about:blank
// @description    Makes sure that users are never remembered, this being a public computer.
// ==/UserScript==

// Created by Ryan O'Hara (minitech), a customer.
// Enjoy my first Greasemonkey script!
// http://git.io/ry

function mtDisable() {
	var items = [];
	items.push(document.querySelector('#PersistentCookie'));
	items.push(document.querySelector('#persistent'));
	items.push(document.querySelector('[name=KMSI]'));
	items.forEach(function(item) {
		if(item) {
			item.disabled = true;
			item.title = 'This was disabled because you\'re using a public computer! If you really mean it, press Ctrl+Alt+A to re-enable.';
		}
	});

	var ran = false;
	window.addEventListener('keydown', function(e) {
		if(e.keyCode === 65 && e.ctrlKey && e.altKey) {
			if(ran) {
				return;
			}

			ran = true;

			e.preventDefault();
			items.forEach(function(item) {
				if(item) {
					item.disabled = false;
					item.title = null;
				}
			});
		}
	}, false);
}

window.addEventListener('DOMContentLoaded', mtDisable);
window.addEventListener('load', mtDisable); // Hotmail apparently re-enables in DOMContentLoaded or similar so we need this too.