This is why designs usually require the voter to be able to inspect the paper ballot before finalizing it. Shenanigans like that would be caught, as the machine has no way of knowing how close the voter will look.
In yesterday’s California election (Los Angeles County, specifically), it had me review all of my choices on the screen (after I was done), then it printed out the form so I could review the printed copy. Then (very confusingly) the final step was to insert the form back into the machine. Basically everyone was confused by this review and reinsert process, but still it seemed like a good system for ensuring there are no glitches.
You could also just replace all that with a paper ballot.
I have had arguments with disability activists about this- apparently, some interpretations of American disability rights legislation require electronic devices to be made available to allow voters whose disability prevents them using a pen to mark their ballot unassisted.