Depending on the rules, maybe, maybe not. In my hometown growing up, you were allowed to vote for any number of candidates up to the number of seats
As far as I can see it, your options are
- Require exactly S candidates be marked
- Allow up to S candidates to be marked
- Allow any number of marks (Approval)
If a bullet vote spoils your ballot, that means you’re working option #1, which I find problematic, because it precludes an honest ballot marking fewer than S candidates.
I mean, I understand the reasoning behind it (preventing the strategy of disingenuous bullet voting, increasing the likelihood of majority support [on paper] for all seated candidates), but I’m not comfortable with it, because I suspect it would be likely to result in a pathology analogous to the Dark Horse +3 problem that Borda has.
Specifically, I’m concerned that if you have to vote for S candidates, and a given voter approves of X<S candidates, voters might additionally include disingenuous approvals of (X-S) “Worst option(s) available” candidates, to prevent other candidates from replacing their preferred candidate. In aggregate, that could end up with one or more “worst candidate” being elected, which is how Borda ends up with negative VSE under 100% strategy.
If there are enough acceptable candidates, that wouldn’t happen, sure, but if there are enough acceptable candidates, you don’t need to require a minimum number of approvals.