The point is that setting a pin, password, pattern or other unlock -- on the phone or any individual application -- DOES NOT prevent ICS's new task manager from displaying thumbnail screenshots of recent browser, email, text, etc. activity.
To chanchano5: The thumbnails ARE NOT too small to read thetext is displayed, including the names of senders/recipients, the content of emails/text messages, or the website last browsed and what is displayed on it.
To EarlyMon: A long press of the home key has always brought up recent apps. But only since ICS does it bring up thumbnails displaying text and activity. As for the boot/shut down tunes, it's true that reducing the ringer to silent silences these tunes. But who wants to have to do that every time they turn their phone off?
Bottom line: ICM's task manager displays revealing thumbnails of all currently loaded applications, bypassing all privacy and lock settings, making a mockery of google's/android's supposed commitment to privacy.