Here are some things I've learned over the years from dealing with these "friendly requests"
The first thing is that many people don't understand what we do and that just because we work with computers doesn't mean we can do everything. Most do not understand what is the difference between programming to design work, or between a design-centric site and a code-centric site.
I usually provide the example of the Coca Cola site (or any other name brand PR-centered site that is heavy on flash) versus a website that is centered around functionality (like their online banking experience). I explain to them that functionally-intensive sites are created by developers, while pretty PR sites are generated by ad people and graphic designers, just like ads in the paper or newspaper commercial. I've found that most people want something that is aesthetic rather than functional (because "they want to get on the web"). I do not personally have the skill or the time for it. At a minimum, this will indicate to them that they may want a professional designer. I think this is critical because over the years people have become pickier about the experience they expect from website. 10 years ago, something from Microsoft Frontpage looked good enough.
The second thing is that people don't seem to understand is that a web presence isn't going to necessarily earn them more money. If they're a neighborhood bar or a small mom-and-pop shop, they can at best get the benefit of a "yellow pages" presence with some extra (e.g., online menus, coupons, etc.).
Third, they may want to consider skipping the web presence at all and using social networking tools. Again, I've met folks who don't really understand the difference. Being on the web doesn't mean you're on Twitter (even though twitter is always shown on CNN).
Fourth, there is such a concept as copyrights. You can't just use fonts, images, scripts and things that are not in the public domain, and you may have to pay extra.