The inspiration to make this thread came from KH-Vids, where they're currently holding their annual user awards. The vote results in the polls staff makes are always made public, but a couple staff members forgot to make results public in some of the threads they made. Earlier ones were somehow able to get fixed by the owner of the poll, but some more recent ones I'm not sure can be fixed.
Doing some testing on our test site, it seems that once someone votes, the option to display votes publicly disappears, and not even staff members can change it. However, if the option to display votes publicly is enabled and someone votes, it can still be changed back to be not public.
This is where more user group permissions would come in handy, giving us the ability to do things like make votes public even once a vote has been cast.