I can see the appeal, if you're hiring for someone who can, eventually, figure out how to do what you want them to. However, if you're hiring for people with a common knowledge base (i.e. computer scientists), who will be required to think up novel solutions to problems that cannot be found online, then you're not going to get the right kind of candidate (and should, instead, be offering double what you would have to that friend who got the answer in 5 min, over the phone, with all the communication issues that presents, to what took the original interviewer 10 or 20+ minutes to figure out they couldn't do by themselves).
In short, if you're trying to hire someone to do work that's been done elsewhere many times before, then this is probably fine. But I don't expect the most innovative companies to ever want to filter for google skills.
In short, if you're trying to hire someone to do work that's been done elsewhere many times before, then this is probably fine. But I don't expect the most innovative companies to ever want to filter for google skills.