I went to check the election results after the Ask Ubuntu and noticed that there were download links to the GPL-licensed OpenSTV without a link to or an offer to provide the source code, as required by the GPL:
You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:
a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
b) Accompany it with a written offer, valid for at least three years, to give any third party, for a charge no more than your cost of physically performing source distribution, a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
c) Accompany it with the information you received as to the offer to distribute corresponding source code. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form with such an offer, in accord with Subsection b above.) – GNU General Public License version 2, section 3
However, on sites where I don't have enough rights to vote, such as Gaming.SE, the page does link to the source code, although it's still not GPL compliant because it's hosted by a third party.
Now, as far as I can tell from reviewing the source code linked to when not logged in / not having enough reputation to vote, the program was written by a single author, so you may have gotten permission from the author to distribute it under a proprietary license; I can't tell if this is what Jeff means in his answer on a related question.
(The linked source code repository also had some problems with files that likely didn't belong in it being present; it would be nice to be able to compare it original, unmodified source code if StackExchange still has it.)
Anyway, I feel it would be a good thing to provide the source code regardless if you've got permission to do so without, if only to be consistent.
Also, it's a bit ironical to only offer Mac & Windows versions of the program at the Ask Ubuntu election results page. It worked fine with Wine, though.
TL;DR: please link to the OpenSTV source even for people who have enough reputation to vote.