so true, an easy and inexpensive search will reveal much about a person they aren't willing to tell... especially at the beginning.
age, marital history, where they've lived, relatives and even credit history... oh, and whether or not they have a criminal history... kind of a good way to gauge if they are willing to lie even about the little things.
this guy i dated not long ago was unwilling to give any personal firm info that would allow me to find anything on him... he lived out of a hotel for the past six months and said that prior to that he lived on the opposite coast. even his email was designed to only show his first name along with the fact that he likes cycling...

i asked him if he was married - he said no - but my tried and true radar was screaming MARRIED.