This is what I told her about Ohio "voter caging":
Voting in US is a federal right but administered by states and subject to the vagaries of state regulations. Ohio allows these mailings, which don't come from the election office but from opposition party operatives. It allows the opposition to use a part of the state law that allows them to challenge a person's eligibility to vote, or accuse them of voter fraud based on the allegation that they don't live where they stated they lived when they registered to vote. The do not forward order means the official looking "voter notice" may not be sent on to the voter in time for them to change their address, or may be sent to an inaccurate address on purpose.
Ohio is one of the worst states for this kind of shenanigans and why we are all going there at the end of October. Welcome to the US system of voter "rights".