Following up on this post, let's take a look at the flip side of the possibility that political parties can help themselves out significantly by taking umbrage with competitors' treatment of them - which is the success (or lack thereof) of exactly that strategy over the past decade.
As I've pointed out before, while 2004 might be the last example of an outrage-based strategy substantially shifting poll numbers, there are more recent cases where it's been tried.
Indeed, the Libs have regularly attempted to make political hay out of the claim that the Cons aren't playing fair. And it's undoubtedly been a fair allegation.
But the general public has never accepted any of the Libs' recent complaints as a reason to either support the Libs or turn against the Cons. While there may be some moments where calling out an opponent for playing politics offers a meaningful chance to tell a leader's own story, a failed attempt to tug at the public's heartstrings can backfire significantly by making the leader appear to be out of touch with voters.
To be fair, there is one other noteworthy goal in raising a complaint about an opponent even if it falls short of earning a response from the wider public: it might manage to rally partisan forces, offering a sense of shared grievance which might help keep current supporters in the fold while also serving as practice to amplify a party message for when a more compelling issue comes up. And it's possible the Libs' past complaints about Con unfairness have accomplished that much.
I'd also note as an aside that concerns about fairness are far more likely to be useful as a defensive rather than an offensive maneuver.
Particularly during the course of an election campaign, though, I'd think a party would want to avoid spending meaningful time and political capital highlighting all but the most obviously-intolerable personal slights - lest it otherwise be seen as missing the point of what voters care about for themselves.