+1
Very good idea. Abuse could be circumvented other ways, for example it would be not hard to write algorythms which would check same IP accs. from time to time for suspicious activity. If an acc is only used to push another, it can be easily identified. Or other measures could be in place, for example not letting do certain actions on another acc from the same IP, for example you couldn't put FPs on the other's GB.
There are a lot of ways to do this, it all depends on the willingness, but in overall it could help the player base further. In todays world, there can be many reasons why there would be more players from the same IP, including parent/child, brothers and sisters, friends sharing same flat etc. It's not reasonable to simply deny them playing, a better approach would be to make sure it can't be used for cheating.