If you are going to rig an election machine you'd do it on the backend, not on the front end where people can see an incorrect choice.

The machine in the video was made by iVotronic, not Diebold.

none of these machines are open-source, that's really the important factor

This is the least important factor.

iVotronic has had problems like this for a long time. For instance see http://www.brennancenter.org/content/resource/letter_to_secr....

If they made the machine, it is probably incompetence. iVontronic looks like it is owned by Printelect, which is owned by Owen Andrews, who seems to be affiliated with the Democrats.

iVotronic is the name of the voting Machine, not the company.

In fact, the iVotronic Machines were indeed created by and originally manufactured by Diebold, though it was sold to another company in 2009.