Yet another example...People applying for research/academic faculty positions at universities usually come and give what are known as "job talks" where they talk about (some of) their research and the current faculty are allowed to ask questions, etc. This is absolutely an assessment of their skills and abilities within their field.
Another point I'd want to make is that many fields, such as law or medicine, have formalized, comprehensive tests that are administered and scored by a recognized organization, e.g. the bar exam or medical board exams. IT certifications come nowhere near those tests in so many ways and as such, technical interviews for a technical position in IT shouldn't be considered out of line with what other professional fields go through, as I see it...
So wait, you are saying that MCSE and CCNE certifications have no merit? The test facilities are run independently by a recognized organization. Why did we spend all that time and money and study so hard? Have you ever taken one of the test?
Why won't sharks eat lawyers? Professional courtesy.