With search results, the spam is more often than not Made for AdSense sites that the average user doesn't realize are pure garbage. Then there are the mass-produced content sites like eHow that most technical people realize are worthless, but the average user loves. It isn't often you see Viagra sites popping up in searches for woodworking. It does happen occasionally though.
So no, I am pretty confident a majority of users would not utilize effectively a feature like that.