People who do the recommended security updates shut down their computers quite often. And yes, sleep reliability varies a lot with the hardware (unfortunately).
I was really surprised when I saw my mother using Safari on her iPhone (which we gave her for christmas just to have a "simple" phone and iPod, nothing more). It's not like she can't use a PC, but she rarely does so.
This made me think that an iPad, or a similar super simple tablet is the right product for her. Appliance is the way to go.
If my parents TV set took 5 minutes to boot up and frequently asked to download and install the latest security updates before letting them watch TV, maybe they would do it less often. :)
Actually, this is a really brilliant idea. Combine it with push notifications and you have a service that could actually be dead simple and replace a lot of the common print jobs at my work.