caught on camera

So I often have the problem of my friends and family guessing my password then logging on my computer, using it, logging out, and I come back hours later often wondering "hmmmm who logged on last?" now for me at least it would be a pain if the computer just told you what time or where you logged in last, I will never be able to guess if it was me that logged in at that specific time. (at least in most circumstances) so why not when you log on if you have a web cam set up with your laptop, desktop, ect. the computer will take a quick snapshot of the user facing the screen and save the picture, then next time you log onto your computer it will show a little pop up in the corner of the picture taken from the last login, maybe archiving them if the user wishes, now of course you could turn this feature off if you so felt the need.

1. user correctly types in password 2. after computer finishes loading desktop ect. webcam turns on and snaps a photo of current user. 3. user loggs of .... .... 9 hours later

4. new user logs into computer and is shown the picture that was taken earlier.

now this would work very well with any laptop, first off they are always right where other people can get at them so they are a big target, and now basically all laptops have some type of camera in them. Now say the person logging in blocks the camera/unplugs the camera/ect. then when you look at the last login picture you will at least know it is time to pick a better password