Its not unambiguous, look at this ballot and tell me who they voted for. It tied a race in Virginia just last year.
https://mobile.twitter.com/virginianpilot/status/94358996960...
https://mobile.twitter.com/virginianpilot/status/94358996960...
Regardless, this is actually the fault of the user rather than machines. As far as I know you can still get a replacement if you do this.