I finally downloaded Google Earth today, yes I know I'm probably the last person on earth who has.
What I found during the installation period wasn't shocking, Google's software was more than happy to change my default search engine in Internet Explorer to Google as well as install their toolbar.
Both were pre-checked.
I unchecked them, I'm more than happy with my current setup.
Most people won't. Most people trust them, they'll follow their lead, they have positive press.