Depends on the nature of the research. But for formal research, it is frowned upon.
Read the article at this link.
Let's say this is done at the mall and you are trying to get public opinion about a new movie that
just has been released. Perhaps this strategy may be accurate.
Now let's say your on Burbon St. in New Orleans and you employ this strategy while trying
to gain public opinion about you is going to win the superbowl next year. It is safe to say
there will not be much bias towards the Packers or the Patriots.