How the poll workers knew to trash our BALLOTS unopened

From Rumble. A brief video made by a woman before the elections – but the point remains the same. WHY do the ‘confidential’ return ballot envelopes tell whether someone is a registered Republican or Democrat on the back, in the barcode, via a single letter? Wouldn’t that make it extra easy to put the Trump ones in one pile (anyone seen the videos of the ballots dumped by the side of the road, at the dump, shredded in a bag etc.) and then get rid of them? She probably wouldn't have noticed except both her and her brother who live at the same address requested a mail-in-ballot so she was able to compare the differences in the barcode. Wonder if this has always been the way mail-in ballots are done or if this was a special for this year.