That they can't hire the right people.

Seriously, employers that are able to "feel" out the right people don't need tests, they'll go with their gut instincts, just like smart business people.

Employers that give IQ tests usually lack this skill and have been burned because of it. I wouldn't want to work at a place that I couldn't trust to find high quality colleagues for me to build with.

(This from a person that naturally scores in the 130's in IQ tests)