What is the major problem with the straw vote polling technique?

A straw vote is an unofficial poll or vote taken to determine the opinion of a group or the public on some issue. It is often used to poll the public to see which candidate they favor and why, though it is not reliable for exact results. The vote can easily be strewed by polling in only select locations that give the answers one seeks and also by choosing to poll in venues that have charged a registration fee which allows the wealthy to buy more seats to events there fore more votes.