This to discourage multi-accounts and farming.
You mean to say, that is not strictly forbidden already? I ask because multi-accounts tend to completely ruin any game, whether it be a free MMO or a paid-for one. Since voting is locked to IP, shouldn't the whole registration be locked to a single IP, aswell?
You can only have one account yes, but as you know that rule is hard to enforce. We do all we can.
Limiting accounts by IP is not a good idea, it could block a whole school or family to play. I have experience with this sort of thing, and Astro Galaxy was designed in such a way to limit / restrict the multi-account issue. The trades will always be an exchange of solars vs. resources / modules / ships and the markups will be set by market value on public auction, making it hard for someone to transfer solars from one account to another.