In one of my favorite stories of how the hastily adopted mail-in voting systems failed during the pandemic year of 2020, over 223,000 ballots mailed out to voters in Clark County, Nevada, were returned as undeliverable during the Democratic primary there last year due to incorrect or out-of-date addresses on the voter rolls.
That's 223,00 out of 1,325,934 ballots sent out in the state's most populous county, home to Las Vegas, after it decided to automatically send ballots to every eligible voter on the rolls for the June primary. Not only was that 17 percent of all ballots mailed, it's also worth noting that 305,008 ballots were returned and accepted. So that's about three ballots undeliverable for every four that counted.