Trouble with unlocking the achievement?
1. Switch profiles to a guest from the main menu by pressing '
2. Accept the rules by scrolling '
' and pressing '
3. Switch back to your main profile from the main menu by pressing '
' again. I signed out that guest from the guide before pressing any button to start.
4. Select 'Play Online', 'Find Match' by pressing '
' twice and then 'Arenas' by pressing '
5. Use all available votes on any arenas and repeat this in every playlist from the left column. Pressing '
' once to like, twice to dislike, and a third time resets the choice.
EDIT (12 May 2017): The “Registered Voter” achievement has been reported to be fixed after v1.34 patch release. I will leave my solution up just in case.