It's not much different, conceptually, than a popup blocker. I've taught non-technical family members to use it with no issues. Not implementing security because it's hard might not be the best route to take.

None! This results in considerable hand slapping and birthday removal. For the most technically challenged of them, I just went through their list of common pages and trained noscript for them. They generally don't visit a huge range of pages anyway, and for random surfing the text and graphical portions of most pages still work well enough. It's really not been an issue.