Depending on the culture, this could work really well, or really badly. I guess the type of person who would use this technique wouldn't want to work at the type of company who wouldn't want him to, so maybe it's a good filter.
It's also something to consider carefully if under a lot of pressure. It could scare away employers that may not be great, but would be better than nothing.
The immediate response when I mentioned this to a friend was that some companies might not "like you wasting their employees time while they are at work", to which I responded that I would probably not enjoy working there.
In a fast growth company engineers spend a lot of their time on hiring (phone screens, multiple in person interviews, "selling" after the interview). Candidate "screening the company" after a phone screen, but before an interview actually saves engineering hours that would be wasted interviewing a person who won't take an offer.
