In 2005, a GOP official who'd recently moved to WA State from the South challenged the registration of 2000 voters. From descriptions in local news sources, it sounded like part of the issue (aside from blatant voter suppression) was that someone had split house numbers apart from street names ...

...and checked for duplicate house numbers not tied to the street as part of the full address. People who had the same house numbers in completely different cities on completely different streets within King County had their registrations challenged.