Googling, I found this:
> Since the U.S. has a very mobile population and voters rarely inform election officials when they move, voters can often be on the voter rolls in two (or more) different states at one time. Unless states have an efficient way of communicating with one another, itβs possible that they may not be able to identify an individual who is on the rolls in two different states.
https://www.ncsl.org/research/elections-and-campaigns/double...
> You describe it as "ridiculously easy," but you seem to be unaware of the protections that are in place.
It is true I have never actually tried it, so I should say it seems like it would be ridicuously easy. I've still not seen any convincing arguments that protections beyond signature matches would prevent this.
The governments of both states know they moved. The voter registrations were adjusted accordingly.
If you had tried to send in their ballots, your attempt to vote unregistered voters would have been detected.
You describe it as "ridiculously easy," but you seem to be unaware of the protections that are in place.