Hypothetical scenario about voter registration databases

Suppose that one candidate was aware that the entire voter registration database had been compromised or polluted's or hacked, in such a way that large numbers of voters had their registration records altered.

In Florida, for example, this was known to of happened due to motor voter laws. If you had changed your address gotten a new driver license, it would update your voter registration record, but it also overwrote your party affiliation information.

In New York, with large numbers of people voting outside of their district the day after Hurricane Sandy, it seems plausible that many voter registration records were mixed up.

So if ONE candidate knew this, very early on, and arranged to have a GEMS database and an app to do large-scale updates to that registration database, with instructions to only fix the registration records of those contacted as leaning towards that particular candidate, it would not exactly be a crime, would it? In fact, if that candidate simply concentrated their resources time and energy on such registration crew error correction, they could probably obtain a significant advantage, if the database initially was actually riddled with errors.

It is not necessary to believe that one candidate maliciously and intentionally corrupted the records of supporters predominantly belonging to the other candidate. Simply remaining quiet about large scale errors, while nonetheless working to correct them, would be huge advantage. Easy to rationalize... Couldn't you call it a superior ground game?