I know that my mom and wife both use Google as their "address bar". My wife wanted to go somewhere the other day (she had to use my Linux box; I playing around with Vista on the Windows one), and I told her to just type the address in the address bar (it was like JcPenney's or something). She said, "I don't want to type it in the address bar, I just want to type it in Google." Google is the default page on my Win PC. My mom does the same thing; she never uses the address bar. She usually asks, "How do I do that?" when I tell her to just type it in.
Back when I was employed at an ISP, we had a Google search box on our main page. Whenever our main page was down for updates or screwups, we *always* got calls from users asking when the page would be back up so they could surf the web. They would use the Google search box to get around the Internet instead of using the address bar or using a different search engine.
It's not far fetched that they will lose traffic if Google doesn't index them in their search results.