here in texas. >> i'm going to walk through the checks and balances again. >> reporter: hayes list county elections said with widespread hacking would never succeed. >> if you even change a period, a period in the election programming, it sends up a red flag that immediately stops the entire process into we can identify what would have triggered that red flag. >> reporter: in harris county alone, they suspect thousands of voting machines. >> six months out we start checking all 13,000 pieces of equipment in harris county, opening them up, do they turn on, have they been tampered with, are all the buttons working. >> reporter: they run accuracy test under the watchful eyes of observers. on election day, they track the number of people showing up to vote and the number of ballots cast. one that would catch them inflated by phantom voters >> somebody would have to find a way to break into the voter