Keith Stanovich argues that IQ tests not only miss personality traits such as agreeableness and conscientiousness but also purely cognitive abilities. These other cognitive abilities he terms "rationality". His ideas are very well summarized here:
http://lesswrong.com/lw/2g1/what_intelligence_tests_miss_the_psychology_of/
Thompson makes some interesting comments on the topic of Stanovich: http://drjamesthompson.blogspot.com/2014/02/the-many-headed-hydra-of-alternate.html
I've never heard of anyone saying "I thought that person was really intelligent, but they turned out not to be", and when there are scandals about people with fake credentials, they don't seem to come from people with fake credentials making mistakes-- instead, someone checks the history.
It seems to me that you can find out a lot about people's intelligence by talking with them a little, though I've underestimated people who were bright enough but didn't present as intellectual.
The real problems are with identifying conscientiousness, benevolence, and loyalty-- that's where the unpleasant surprises show up.