Nothing says the current user of the machine is the tech-savvy installer. My mother's comp has no-script on it, but she is in no way strong technologically.
A "mom-level" user may well enable scripts when prompted by an artful redirect like say:
1. A clone of your bank website (if you were headed there)
2. A page-not-found or server error page that looked normal..
Funny, there was just a discussion here yesterday asking "Why would anybody use NoScript?"