Given that the devs think it appropriate that a failed leecher report should result in a multiplier loss to dissuade people from rampant, illegitimate leecher-reporting, I think it reasonable that the same should apply to failed kick/ban polls.
Polling doesn't really work right now. Perhaps in them most egregious cases, as if someone just goes on a TK rampage, there tends to be a successful ban. But in general, polling is often so ridiculously frequent that players simply have no time to seriously evaluate the legitimacy of a poll. Many ignore it, or automatically vote '2', or just vote randomly. No doubt this is exasperated by the fact that many pollers don't explain the reason for their poll - or at least not until well after it has been submitted. And in any case, how am I to know if the poller is correct in calling a tk intentional, or that they themselves did not first attack a teammate?
A penalty for failed polls should 1) reduce the number of polls, and 2) encourage poll-submitters to state their reasons before submitting the poll, so the poll is more likely to be successful. With fewer polls and better polling etiquette, more players would take voting seriously and polling could become a more useful tool rather than the annoyance it is now.