I understand the idea, but the question is, what score is considered "safe"? WOT uses numerical averages from 0-100. Is 80 safe? 70?
Another issue is "ballot-box stuffing". Sites have an incentive to get good reviews posted (by employees, friends, etc.), and competitors may get bad reviews posted for that site or product. WOT should be used only as one more data point, and it's more important to read the reviews than to go blindly by numerical score.
Here's a good example:
http://forums.informaction.com/viewtopic.php?f=7&t=8462. It's a long thread that doesn't need to be read, but the pertinent post is
this one.
Checking just now, the mywot score is lower than when that thread occurred, possibly because of publicity from that thread. But when I first checked it, IIRC it was in the 70s or so. The older reviews were favorable. But just reading the first two (most recent) set off alarms.
Suggestions: Read
SOME SITES YOU MIGHT NOT WANT TO ALLOW, and perhaps mark them as Untrusted on grandparents' machine, which means that they'll never even show in the main menu.
Same with
List of scripts for which NS runs surrogate, which you can safely mark as Untrusted, because the
Surrogate Script will always run, thus not breaking the page. And ask them to read
NoScript Quick Start Guide, and
FAQ: "What Is A Trusted Site?".
Most home users, especially novices like your folks, tend to have a pretty standard list of sites they visit: e-mail, news, shopping, finance, etc. If you configure those sites *once* for them, that should be a big help.
It's certainly attractive to try to automate trust decisions (and this is hardly the first time it's been brought up), but unfortunately, in the ever-changing world of the Internet, the most crucial component is the one at the keyboard.
Also let grandparents know of this forum, so that if they have questions after reading the above material, they can post here.
(I sympathize. All of my family, and most of my RL friends, are non-tech, so for questions about *anything*, guess whom they call?

)