Maybe someone in Google thinks this is a good idea but I doubt they will think that for long. Having run into Captcha several times I started to use other search engines.
If I'm doing it others will do it too. So Wall Street should not be surprised if Google's profit is down in the next two quarters.
Search spam is a problem one which we experienced firsthand. We had invested quite a bit of money in a meta search engine but search spam had become such a problem we decided to drop the meta engine and took quite a loss in time and money.
I can see why Google is addressing this problem but using captcha is not a solution.
There are many ways to prevent some of this abuse but using automated blocking of any kind in my opinion is not the way to go.
Nothing works better than human intervention where a person can decide what is search spam and what is normal search habits people may have.
And if found to be spam then proper action should be contacting the ISP or Host and informing them.
But I guess Google will at some point notice it's ad revenue is down and someone in upper management will be given the task to find out why. That person will have to write a report on what his department found. The report will be presented at a meeting and will include recommendations on what actions should be taken.
In the end someone will lose their job for coming up with an idea that cost the company millions of dollars in lost ad revenue.
A mistake that one would not want to put on their job resume.
In the end Captcha will be gone and a new person will head up that department.
So I guess until then I will use Bing or Yahoo.