UGH. Preventing forwarding does two things
A ) insured that precinct information is correct. - If you don't get your package, it means they don't have the correct address data. If they don't have the correct data, then you are probably listed in the wrong precinct. Its up to the recipient to insure their address is correct, not the Governments.
B ) helps prevent fraud by keeping old/outdated/deceased voter data off the streets.
I see no downside.